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Winter protection of plants.
If the ground is not ready for planting in the fall, or if it is desired for any reason to delay until spring, the trees or bushes may be heeled-in, as illustrated in Fig. 151. The roots are laid in a furrow or trench, and are covered with well-firmed earth. Straw or manure may be thrown over the earth still further to protect the roots, but if it is thrown over the tops, mice may be attracted by it and the trees be girdled. Tender trees or bushes may be lightly covered to the tips with earth. Plants should be heeled-in only in loose, warm, loamy or sandy ground and in a well-drained place.
Fall-planted trees should generally be mounded up, sometimes even as high as shown in Fig. 152. This hilling holds the plant in position, carries off the water, prevents too deep freezing, and holds the earth from heaving. The mound is taken away in the spring. It is sometimes advisable to mound-up established trees in the fall, but on well-drained land the practice is usually not necessary. In hilling trees, pains should be taken not to leave deep holes, from which the earth was dug, close to the tree, for water collects in them. Roses and many other bushes may be mounded in the fall with profit.
It is always advisable to mulch plants that are set in the fall. Any loose and dry material—as straw, manure, leaves, leafmold, litter from yards and stables, pine boughs—may be used for this purpose. Very strong or compact manures, as those in which there is little straw or litter, should be avoided. The ground may be covered to a depth of five or six inches, or even a foot or more if the material is loose. Avoid throwing strong manure directly on the crown of the plants, especially of herbs, for the materials that leach from the manure sometimes injure the crown buds and the roots.
This protection may also be given to established plants, particularly to those which, like roses and herbaceous plants, are expected to give a profusion of bloom the following year. This mulch affords not only winter protection, but is an efficient means of fertilizing the land. A large part of the plant-food materials have leached out of the mulch by spring, and have become incorporated in the soil, where the plant makes ready use of them.
Mulches also serve a most useful purpose in preventing the ground from packing and baking by the weight of snows and rains, and the cementing action of too much water in the surface soil. In the spring, the coarser parts of the mulch may be removed, and the finer parts spaded or hoed into the ground.
Tender bushes and small trees may be wrapped with straw, hay, burlaps, or pieces of matting or carpet. Even rather large trees, as bearing peach trees, are often baled up in this way, or sometimes with corn fodder, although the results in the protection of fruit-buds are not often very satisfactory. It is important that no grain is left in the baling material, else mice may be attracted to it. (The danger of gnawing by mice that nest in winter coverings is always to be anticipated.) It should be known, too, that the object in tying up or baling plants is not so much to protect from direct cold as to mitigate the effects of alternate freezing and thawing, and to protect from drying winds. Plants may be wrapped so thick and tight as to injure them.
The labor of protecting large plants is often great and the results uncertain, and in most cases it is a question whether more satisfaction could not be attained by growing only hardy trees and shrubs.
The objection to covering tender woody plants cannot be urged with equal force against tender herbs or very low bushes, for these are protected with ease. Even the ordinary mulch may afford sufficient protection; and if the tops kill back, the plant quickly renews itself from near the base, and in many plants—as in most hybrid perpetual roses—the best bloom is on these new growths of the season. Old boxes or barrels may be used to protect tender low plants (Figs. 153, 154). The box is filled with leaves or dry straw and either left open on top or covered with boards, boughs, or even with burlaps (Fig. 154).
Connoisseurs of tender roses and other plants sometimes go to the pains of erecting a collapsible shed over the bush, and filling with leaves or straw. Whether this is worth while depends wholly on the degree of satisfaction that one derives from the growing of choice plants (see Roses, in Chap. VIII).
The tops of plants may be laid down for the winter. Figure 155 shows a method of laying down blackberries, as practiced in the Hudson River valley. The plants were tied to a trellis, as the method is in that country, two wires (a, b) having been run on either side of the row. The posts are hinged on a pivot to a short post (c), and are held in position by a brace (d). The entire trellis is then laid down on the approach of winter, as shown in the illustration. The blackberry tops are so strong that they hold the wires up from the ground, even when the trellis is laid down. To hold the wires close to the earth, stakes are thrust over them in a slanting position, as shown at n n. The snow that drifts through the plants ordinarily affords sufficient protection for plants which are as hardy as grapes and berries. In fact, the species may be uninjured even without cover, since, in their prostrate position, they escape the cold and drying winds.
In severe climates, or in the case of tender plants, the tops should be covered with straw, boughs, or litter, as recommended for regular mulch-covers. Sometimes a V-shaped trough made from two boards is placed over the stems of long or vine-like plants that have been laid down. All plants with slender or more or less pliant stems can be laid down with ease. With such protection, figs can be grown in the northern states. Peach and other fruit trees may be so trained as to be tipped over and covered.
Laid-down plants are often injured if the covering remains too late in the spring. The ground warms up early, and may start the buds on parts of the buried plants, and these tender buds may be broken when the plants are raised, or injured by sun, wind, or frost. The plants should be raised while the wood and buds are still hard and dormant.
Pruning.
Pruning is necessary to keep plants in shape, to make them more floriferous and fruitful, and to hold them within bounds.
Even annual plants often may be pruned to advantage. This is true of tomatoes, from which the superfluous or crowding shoots may be removed, especially if the land is so rich that they grow very luxuriantly; sometimes they are trained to a single stem and most of the side shoots are taken away as they appear. If plants of marigold, gaillardia, or other strong and spreading growers are held by stakes or wire-holders (a good practice), it may be advisable to remove the weak and sprawling shoots. Balsams give better results when side shoots are taken off. The removing of the old flowers, which is to be advised with flower-garden plants (page 116), is also a species of pruning.
Distinction should be made between pruning and shearing. Plants are sheared into given shapes. This may be necessary in bedding-plants, and occasionally when a formal effect is desired in shrubs and trees; but the best taste is displayed, in the vast majority of cases, in allowing the plants to assume their natural habits, merely keeping them shapely, cutting out old or dead wood, and, in some cases, preventing such crowding of shoots as will reduce the size of the bloom. The common practice of shearing shrubbery is very much to be reprehended; this subject is discussed from another point of view on page 24.
The pruner should know the flower-bearing habit of the plant that he prunes,—whether the bloom is on the shoots of last season or on the new wood of the present season, and whether the flower-buds of spring-blooming plants are separate from the leaf-buds. A very little careful observation will determine these points for any plant. (1) The spring-blooming woody plants usually produce their flowers from buds perfected the fall before and remaining dormant over winter. This is true of most fruit-trees, and such shrubs as lilac, forsythia, tree peony, wistaria, some spireas and viburnums, weigela, deutzia. Cutting back the shoots of these plants early in spring or late in fall, therefore, removes the bloom. The proper time to prune such plants (unless one intends to reduce or thin the bloom) is just after the flowering season. (2) The summer-blooming woody plants usually produce their flowers on shoots that grow early in the same season. This is true of grapes, quince, hybrid perpetual roses, shrubby hibiscus, crape myrtle, mock orange, hydrangea (paniculata), and others. Pruning in winter or early spring to secure strong new shoots is, therefore, the proper procedure in these cases.
Remarks on pruning may be found under the discussion of roses and other plants in subsequent chapters, when the plants need any special or peculiar attention.
Fruit-trees and shade-trees are usually pruned in winter, preferably late in winter, or in very early spring. However, there is usually no objection to moderate pruning at any time of the year; and moderate pruning every year, rather than violent pruning in occasional years, is to be advised. It is an old idea that summer pruning tends to favor the production of fruit-buds and therefore to make for fruitfulness; there is undoubtedly truth in this, but it must be remembered that fruitfulness is not the result of one treatment or condition, but of all the conditions under which the plant lives.
All limbs should be removed close to the branch or trunk from which they arise, and the surface of the wound should be practically parallel with such branch or trunk, rather than to be cut back to stubs. The stubs do not heal readily.
All wounds much above an inch across may be protected by a coat of good linseed-oil paint; but smaller wounds, if the tree is vigorous, usually require no protection. The object of the paint is to protect the wound from cracking and decay until the healing tissue covers it.
Superfluous and interfering branches should be removed from fruit-trees, so that the top will be fairly open to sun and to the pickers. Well-pruned trees allow of an even distribution and uniform development of the fruit. Watersprouts and suckers should be removed as soon as they are discovered. How open the top may be, will depend on the climate. In the West, open trees suffer from sun-scald.
The fruit-bearing habit of the fruit-tree must be considered in the pruning. The pruner should be able to distinguish fruit-buds from leaf-buds in such species as cherries, plums, apricot, peach, pear, apple, and so prune as to spare these buds or to thin them understandingly. The fruit-buds are distinguished by their position on the tree and by their size and shape. They may be on distinct "spurs" or short branches, in all the above fruits; or, as in the peach, they may be chiefly lateral on the new shoots (in the peach, the fruit-buds are usually two at a node and with a leaf-bud between them), or, as sometimes in apples and pears, they may be at the ends of last year's growths. Fruit-buds are usually thicker, or "fatter," than leaf-buds, and often fuzzy. Heading-back the tree of course tends to concentrate the fruit-buds and to keep them nearer the center of the tree-top; but heading-back must be combined with intelligent saving and thinning of the interior shoots. Heading-back of pears and peaches and plums is usually a very desirable practice.
Tree surgery and protection.
Aside from the regular pruning to develop the tree into its best form to enable it to do its best work, there are wounds and malformations to be treated. Recently, the treating of injured and decayed trees has received much attention, and "tree doctors" and "tree surgeons" have engaged in the business. If there are quacks among these people, there are also competent and reliable men who are doing useful service in saving and prolonging the life of trees; one should choose a tree doctor with the same care that he would choose any other doctor. The liability of injury to street trees in the modern city and the increasing regard for trees, render the services of good experts increasingly necessary.
Street trees are injured by many causes: as, starving because of poor soil and lack of water under pavements; smoke and dust; leakage from gas mains and from electric installation; gnawing by horses; butchering by persons stringing wires; carelessness of contractors and builders; wind and ice storms; overcrowding; and the blundering work of persons who think that they know how to prune. Well-enforced municipal regulations should be able to control most of these troubles.
Tree guards.
Along roadsides and other exposed places it is often necessary to protect newly set trees from horses, boys, and vehicles. There are various kinds of tree guards for this purpose. The best types are those that are more or less open, so as to allow the free passage of air and which are so far removed from the body of the tree that its trunk may expand without difficulty. If the guards are very tight, they may shade the trunk so much that the tree may suffer when the guard is removed, and they prevent the discovery of insects and injuries. It is important that the guard does not fill with litter in which insects may harbor. As soon as the tree is old enough to escape injury, the guards should be removed. A very good guard, made of laths held together with three strips of band-iron, and secured to iron posts, is shown in Fig. 156. Figure 157. shows a guard made by winding fencing wire upon three posts or stakes. When there is likely to be danger from too great shading of the trunk, this latter form of guard is one of the best. There are good forms of tree guards on the market. Of course hitching-posts should be provided, wherever horses are to stand, to remove the temptation of hitching to trees. Figure 158, however, shows a very good device when a hitching post is not wanted. A strong stick, four or five feet long, is secured to the tree by a staple and at the lower end of the stick is a short chain with a snap in the end. The snap is secured to the bridle, and the horse is not able to reach the tree.
Mice and rabbits.
Trees and bushes are often seriously injured by the gnawing of mice and rabbits. The best preventive is not to have the vermin. If there are no places in which rabbits and mice can burrow and breed, there will be little difficulty. At the approach of winter, if mice are feared, the dry litter should be removed from about the trees, or it should be packed down very firm, so that the mice cannot nest in it. If the rodents are very abundant, it may be advisable to wrap fine wire netting about the base of the tree. A boy who is fond of trapping or hunting will ordinarily solve the rabbit difficulty. Rags tied on sticks which are placed at intervals about the plantation will often frighten rabbits away.
Girdled trees.
Trees that are girdled by mice should be wrapped up as soon as discovered, so that the wood shall not become too dry. When warm weather approaches, shave off the edges of the girdle so that the healing tissue may grow freely, smear the whole surface with grafting-wax, or with clay, and bind the whole wound with strong cloths. Even though the tree is completely girdled for a distance of three or four inches, it usually may be saved by this treatment, unless the injury extends into the wood. The water from the roots rises through the soft wood and not between the bark and the wood, as commonly supposed. When this sap water has reached the foliage, it takes part in the elaboration of plant-food, and this food is distributed throughout the plant, the path of transfer being in the inner layers of bark. This food material, being distributed back to the girdle, will generally heal over the wound if the wood is not allowed to become dry.
In some cases, however, it is necessary to join the bark above and below the girdle by means of cions, which are whittled to a wedge-shape on either end, and inserted underneath the two edges of the bark (Fig. 159). The ends of the cions and the edges of the wound are held by a bandage of cloth, and the whole work is protected by melted grafting-wax poured upon it. [Footnote: A good grafting-wax is made as follows: Into a kettle place one part by weight of tallow, two parts of beeswax, four parts of rosin. When completely melted, pour into a tub or pail of cold water, then work it with the hands (which should be greased) until it develops a grain and becomes the color of taffy candy. The whole question of the propagation of plants is discussed in "The Nursery-Book."]
Repairing street trees.
The following advice on "tree surgery" is by A.D. Taylor (Bulletin 256, Cornell University, from which the accompanying illustrations are adapted):—
"Tree surgery includes the intelligent protection of all mechanical injuries and cavities. Pruning requires a previous intimate knowledge of the habits of growth of trees; surgery, on the other hand, requires in addition a knowledge of the best methods for making cavities air-tight and preventing decay. The filling of cavities in trees has not been practiced sufficiently long to warrant making a definite statement as to the permanent success or failure of the operation; the work is still in an experimental stage. The caring for cavities in trees must be urged as the only means of preserving affected specimens, and the preservation of many noble specimens has been at least temporarily assured through the efforts of those practicing this kind of work.
"Successful operation depends on two important factors: first, that all decayed parts of the cavity be wholly removed and the exposed surface thoroughly washed with an antiseptic; second, that the cavity, when filled, must be air tight and hermetically sealed if possible. Trees are treated as follows: The cavity is thoroughly cleaned by removing all decayed wood and washing the interior surface with a solution of copper sulfate and lime, in order to destroy any fungi that may remain. The edges of the cavity are cut smooth in order to allow free growth of the cambium after the cavity is filled. Any antiseptic, such as corrosive sublimate, creosote, or even paint, may answer the purpose; creosote, however, possesses the most penetrating powers of any. The method of filling the cavities depends to a great extent on their size and form. Very large cavities with great openings are generally bricked on the outside, over the opening, and filled on the inside with concrete, the brick serving the purpose of a retaining wall to hold the concrete in place. Concrete used for the main filling is usually made in the proportion of one part good Portland cement, two parts sand, and four parts crushed stone, the consistency of the mixture being such that it may be poured into the cavity and require little or no tamping to make the mass solid. (Fig. 160.)
"Fillings thus made are considered by expert tree surgeons to be a permanent preventive of decay. The outside of the filling is always coated with a thin covering of concrete, consisting of one part cement to two parts fine sand. Cavities resulting from freezing, and which, though large on the inside, show only a long narrow crack on the outside, are most easily filled by placing a form against the entire length of the opening, having a space at the top through which the cement may be poured (Fig. 161). Another method of retaining the concrete is to reinforce it from the outside by driving rows of spikes along the inner surface of either side of the cavity and lacing a stout wire across the face of the cavity. For best results, all fillings must come flush with the inner bark when finished. During the first year, this growing tissue will spread over the outer edge of the filling, thus forming an hermetically sealed cavity. In the course of time, the outside of small or narrow openings should be completely covered with tissue, which buries the filling from view.
"It has been found that there is a tendency for portland cement to contract from the wood after it dries, leaving a space between the wood and the cement through which water and germs of decay may enter. A remedy for this defect has been suggested in the use of a thick coat of tar, or an elastic cement which might be spread over the surface of the cavity before filling. The cracking of portland cement on the surface of long cavities is caused by the swaying of trees during heavy storms, and should not occur if the filling is correctly done.
"In addition to the preservation of decayed specimens by filling the cavities, as above outlined, it has been proposed to strengthen the tree by treating it as shown in Fig. 162. Young saplings of the same species, after having become established as shown, are grafted by approach to the mature specimen.
"Injury frequently results from error in the method of attempting to save broken, or to strengthen and support weak branches that are otherwise healthy. The means used for supporting cracked, wind-racked, and overladen branches which show a tendency to split at the forks are bolting and chaining. The practice of placing iron bands around large branches in order to protect them has resulted in much harm; as the tree grows and expands, such bands tighten, causing the bark to be broken and resulting after a few years in a partial girdling (Fig. 163).
"To bolt a tree correctly is comparatively inexpensive. The safest method consists in passing a strong bolt through a hole bored in the branch for this purpose, and fastening it on the outside by means of a washer and a nut. Generally the washer has been placed against the bark and the nut then holds it in place. A better method of bolting, and one which insures a neat appearance of the branch in addition to serving as the most certain safeguard against the entrance of disease, is to counter-sink the nut in the bark and imbed it in portland cement. The hole for the sinking of the nut and washer is thickly coated with lead paint and then with a layer of cement, on which are placed the nut and washer, both of which are then imbedded in cement. If the outer surface of the nut be flush with the plane of the bark, within a few years it will be covered by the growing tissue.
"The inner ends of the rods in the two branches may be connected by a rod or chain. The preference for the chain over the rod attachment is based on the compressive and tensile stresses which come on the connection during wind storms. Rod connections are preferred, however, when rigidity is required, as in unions made close to the crotch; but for tying two branches together before they have shown signs of weakening at the fork, the chain may best be used, as the point of attachment may be placed some distance from the crotch, where the flexibility factor will be important and the strain comparatively small. Elms in an advanced stage of maturity, if subjected to severe climatic conditions, often show this tendency to split. These trees, especially, should be carefully inspected and means taken to preserve them, by bolting if necessary."
The illustrations, Figs. 164-173, are self-explanatory, and show poor practice and good practice in the care of trees.
The grafting of plants.
Grafting is the operation of inserting a piece of a plant into another plant with the intention that it shall grow. It differs from the making of cuttings in the fact that the severed part grows in another plant rather than in the soil.
There are two general kinds of grafting—one of which inserts a piece of branch in the stock (grafting proper), and one which inserts only a bud with little or no wood attached (budding). In both cases the success of the operation depends on the growing together of the cambium of the cion (or cutting) and that of the stock. The cambium is the new and growing tissue lying underneath the bark and on the outside of the growing wood. Therefore, the line of demarcation between the bark and the wood should coincide when the cion and stock are joined.
The plant on which the severed piece is set is called the stock. The part which is removed and set into the stock is called a cion if it is a piece of a branch, or a "bud" if it is only a single bud with a bit of tissue attached.
The greater part of grafting and budding is performed when the cion or bud is nearly or quite dormant. That is, grafting is usually done late in winter and early in spring, and budding may be performed then, or late in summer, when the buds have nearly or quite matured.
The chief object of grafting is to perpetuate a kind of plant which will not reproduce itself from seed, or of which seed is very difficult to obtain. Cions or buds are therefore taken from this plant and set into whatever kind of plant is obtainable on which they will grow. Thus, if one wants to propagate the Baldwin apple, he does not for that purpose sow seeds thereof, but takes cions or buds from a Baldwin tree and grafts them into some other apple tree. The stocks are usually obtained from seeds. In the case of the apple, young plants are raised from seeds which are secured mostly from cider factories, without reference to the variety from which they came. When the seedlings have grown to a certain age, they are budded or grafted, the grafted part making the entire top of the tree; and the top bears fruit like that of the tree from which the cions were taken.
There are many ways in which the union between cion and stock is made. Budding may be first discussed. It consists in inserting a bud underneath the bark of the stock, and the commonest practice is that which is shown in the illustrations. Budding is mostly performed in July, August, and early September, when the bark is still loose or in condition to peel. Twigs are cut from the tree which it is desired to propagate, and the buds are cut off with a sharp knife, a shield-shaped bit of bark (with possibly a little wood) being left with them (Fig. 174). The bud is then shoved into a slit made in the stock, and it is held in place by tying with a soft strand. In two or three weeks the bud will have "stuck" (that is, it will have grown fast to the stock), and the strand is cut to prevent its strangling the stock. Ordinarily the bud does not grow until the following spring, at which time the entire stock or branch in which the bud is inserted is cut off an inch above the bud; and the bud thereby receives all the energy of the stock. Budding is the commonest grafting operation in nurseries. Seeds of peaches may be sown in spring, and the plants which result will be ready for budding that same August. The following spring, or a year from the planting of the seed, the stock is cut off just above the bud (which is inserted near the ground), and in the fall of that year the tree is ready for sale; that is, the top is one season old and the root is two seasons old, but in the trade it is known as a one-year-old tree. In the South, the peach stock may be budded in June or early July of the year in which the seed is planted, and the bud grows into a saleable tree the same year: this is known as June budding. In apples and pears the stock is usually two years old before it is budded, and the tree is not sold until the top has grown two or three years. Budding may be performed also in the spring, in which case the bud will grow the same season. Budding is always done on young growths, preferably on those not more than one year old.
Grafting is the insertion of a small branch (or cion), usually bearing more than one bud. If grafting is employed on small stocks, it is customary to employ the whip-graft (Fig. 175). Both stock and cion are cut across diagonally, and a split made in each, so that one fits into the other. The graft is tied securely with a string, and then, if it is above ground, it is also waxed carefully.
In larger limbs or stocks, the common method is to employ the cleft-graft (Fig. 176). This consists in cutting off the stock, splitting it, and inserting a wedge-shaped cion in one or both sides of the split, taking care that the cambium layer of the cion matches that of the stock. The exposed surfaces are then securely covered with wax.
Grafting is usually performed early in the spring, just before the buds swell. The cions should have been cut before this time, when they were perfectly dormant. Cions may be stored in sand in the cellar or in the ice-house, or they may be buried in the field. The object is to keep them fresh and dormant until they are wanted.
If it is desired to change the top of an old plum, apple, or pear tree to some other variety, it is usually accomplished by means of the cleft-graft. If the tree is very young, budding or whip-grafting may be employed. On an old top the cions should begin to bear when three to four years old. All the main limbs should be grafted. It is important to keep down the suckers or watersprouts from around the grafts, and part of the remaining top should be cut away each year until the top is entirely changed over (which will result in two to four years).
A good wax for covering the exposed parts is described in the footnote on page 145.
Keeping records of the plantation.
If one has a large and valuable collection of fruit or ornamental plants, it is desirable that he have some permanent record of them. The most satisfactory method is to label the plants, and then to make a chart or map on which the various plants are indicated in their proper positions. The labels are always liable to be lost and to become illegible, and they are often misplaced by careless workmen or mischievous boys.
For vegetables, annuals, and other temporary plants, the best labels are simple stakes, like that shown in Fig. 177. Garden stakes a foot long, an inch wide, and three-eighths inch thick may be bought of label manufacturers for three to five dollars a thousand. These take a soft pencil very readily, and if the labels are taken up in the fall and stored in a dry place, they will last two or three years.
For more permanent herbaceous plants, as rhubarb and asparagus, or even for bushes, a stake that is sawed from clear pine or cypress, eighteen inches long, three inches wide, and an inch or more thick, affords a most excellent label. The lower end of the stake is sawed to a point, and is dipped in coal tar or creosote, or other preservative. The top of the stake is painted white, and the legend is written with a large and soft pencil. When the writing becomes illegible or the stake is needed for other plants, a shaving is taken off the face of the label with a plane, a fresh coat of paint added, and the label is as good as ever. These labels are strong enough to withstand shocks from whiffletrees and tools, and should last ten years.
Whenever a legend is written with a lead pencil, it is advisable to use the pencil when the paint (which should be white lead) is still fresh or soft. Figure 178 shows a very good device for preserving the writing on the face of the label. A block of wood is secured to the label by means of a screw, covering the legend completely and protecting it from the weather.
If more ornamental stake labels are desired, various types can be bought in the market, or one can be made after the fashion of Fig. 179. This is a zinc plate that can be painted black, on which the name is written with white paint. Many persons, however, prefer to paint the zinc white, and write or stamp the label with black ink or black type. Two strong wire legs are soldered to the label, and these prevent it from turning around. These labels are, of course, much more expensive than the ordinary stake labels, and are usually not so satisfactory, although more attractive.
For labeling trees, various kinds of zinc tallies are in common use, as shown in Figs. 180 and 181. Fresh zinc takes a lead pencil readily, and the writing often becomes more legible as it becomes older, and it will usually remain three or four years. These labels are attached either by wires, as a, b, Fig. 180, or they are wound about the limb as shown in c, d, and e, in Fig. 180. The type of zinc label most in use is a simple strip of zinc, as shown in Fig. 181, wrapped about the limb. The metal is so flexible that it expands readily with the growth of the branch. While these zinc labels are durable, they are very inconspicuous because of their neutral color, and it is often difficult to find them in dense masses of foliage.
The common wooden label of the nurserymen (Fig. 182) is perhaps as useful as any for general purposes. If the label has had a light coat of thin white lead, and the legend has been made with a soft lead pencil, the writing should remain legible four or five years. Fig. 183 shows another type of label that is more durable, since the wire is stiff and large, and is secured around the limb by means of pincers. The large loop allows the limb to expand, and the stiff wire prevents the misplacing of the label by winds and workmen. The tally itself is what is known as the "package label" of the nurserymen, being six inches long, one and one-fourth inches wide, and costing (painted) less than one and one-half dollars a thousand. The legend is made with a lead pencil when the paint is fresh, and sometimes the label is dipped in thin white lead after the writing is made, so that the paint covers the writing with a very thin protecting coat. A similar label is shown in Fig. 184., which has a large wire loop, with a coil, to allow the expansion of the limb. The tallies of this type are often made of glass, or porcelain with the name indelibly printed in them. Figure 185. shows a zinc tally, which is secured to the tree by means of a sharp and pointed wire driven into the wood. Some prefer to have two arms to this wire, driving one point on either side of the tree. If galvanized wire is used, these labels will last for many years.
It is very important, when adjusting labels to trees, to be sure that the wire is not twisted tight against the wood. Figure 186 shows the injury that is likely to result from label wires. When a tree is constricted or girdled, it is very liable to be broken off by winds. It should be a rule to attach the label to a limb of minor importance, so that if the wire should injure the part, the loss will not be serious. When the label, Fig. 182, is applied, only the tips of the wire should be twisted together, leaving a large loop for the expansion of the limb.
The storing of fruits and vegetables.
The principles involved in the storing of perishable products, as fruits and vegetables, differ with the different commodities. All the root-crops, and most fruits, need to be kept in a cool, moist, and uniform temperature if they are to be preserved a great length of time. Squashes, sweet-potatoes, and some other things need to be kept in an intermediate and what might be called a high temperature; and the atmosphere should be drier than for most other products. The low temperature has the effect of arresting decomposition and the work of fungi and bacteria. The moist atmosphere has the effect of preventing too great evaporation and the consequent shriveling.
In the storing of any commodity, it is very important that the product is in proper condition for keeping. Discard all specimens that are bruised or are likely to decay. Much of the decay of fruits and vegetables in storage is not the fault of the storage process, but is really the work of diseases with which the materials are infected before they are put into storage. For example, if potatoes and cabbages are affected with the rot, it is practically impossible to keep them any length of time.
Apples, winter pears, and all roots, should be kept at a temperature somewhat near the freezing point. It should not rise above 40 deg. F. for best results. Apples can be kept even at one or two degrees below the freezing point if the temperature is uniform. Cellars in which there are heaters are likely to be too dry and the temperature too high. In such places it is well to keep fresh vegetables and fruits in tight receptacles, and pack the roots in sand or moss in order to prevent shriveling. In these places, apples usually keep better if headed up in barrels than if kept on racks or shelves. In moist and cool cellars, however, it is preferable for the home supply to place them on shelves, not piling them more than five or six inches deep, for then they can be sorted over as occasion requires. In case of fruits, be sure that the specimens are not over-ripe when placed in storage. If apples are allowed to lie in the sun for a few days before being packed, they will ripen so much that it is very difficult to keep them.
Cabbages should be kept at a low and uniform temperature, and water should be drained away from them. They are stored in many ways in the field, but success depends so much on the season, particular variety, ripeness, and the freedom from injuries by fungi and insects, that uniform results are rarely secured by any one method. The best results are to be expected when they can be kept in a house built for the purpose, in which the temperature is uniform and the air fairly moist. When stored out of doors, they are likely to freeze and thaw alternately; and if the water runs into the heads, mischief results. Sometimes they are easily stored by being piled into a conical heap on well-drained soil and covered with dry straw, and the straw covered with boards. It does not matter if they are frosted, provided they do not thaw out frequently. Sometimes cabbages are laid head down in a shallow furrow plowed in well-drained land, and over them is thrown straw, the stumps being allowed to project through the cover. It is only in winters of rather uniform temperature that good results are to be expected from such methods. These are some of the main considerations involved in the storing of such things as cabbage; the subject is mentioned again in the discussion of cabbage in Chapter X.
In the storing of all products, especially those which have soft and green matter, as cabbages, it is well to provide against the heating of the produce. If the things are buried out of doors, it is important to put on a very light cover at first so that the heat may escape. Cover them gradually as the cold weather comes on. This is important with all vegetables that are placed in pits, as potatoes, beets, and the like. If covered deeply at once, they are likely to heat and rot. All pits made out of doors should be on well-drained and preferably sandy land.
When vegetables are wanted at intervals during the winter from pits, it is well to make compartment pits, each compartment holding a wagon load or whatever quantity will be likely to be wanted at each time. These pits are sunk in well-drained land, and between each of the two pits is left a wall of earth about a foot thick. One pit can then be emptied in cold weather without interfering with the others.
An outside cellar is better than a house cellar in which there is a heater, but it is not so handy. If it is near the house, it need not be inconvenient, however. A house is usually healthier if the cellar is not used for storage. House cellars used for storage should have a ventilating shaft.
Some of the principles involved in an ice-cooled storage house are explained in the diagram, Fig. 189. If the reader desires to make a careful study of storage and storage structures, he should consult cyclopedias and special articles.
The forcing of plants.
There are three general means (aside from greenhouses) of forcing plants ahead of their season in the early spring—by means of forcing-hills and hand-boxes, by coldframes, and by hotbeds.
The forcing-hill is an arrangement by means of which a single plant or a single "hill" of plants may be forced where it permanently stands. This type of forcing may be applied to perennial plants, as rhubarb and asparagus, or to annuals, as melons and cucumbers.
In Fig. 190 is illustrated a common method of hastening the growth of rhubarb in the spring. A box with four removable sides, two of which are shown in end section in the figure, is placed around the plant in the fall. The inside of the box is filled with straw or litter, and the outside is banked thoroughly with any refuse, to prevent the ground from freezing. When it is desired to start the plants, the covering is removed from both the inside and outside of the box and hot manure is piled around the box to its top.
If the weather is yet cold, dry light leaves or straw may be placed inside the box; or a pane or sash of glass may be placed on top of the box, when it will become a coldframe. Rhubarb, asparagus, sea-kale, and similar plants may be advanced two or four weeks by means of this method of forcing. Some gardeners use old barrels or half-barrels in place of the box. The box, however, is better and handier, and the sides can be stored for future use.
Plants that require a long season in which to mature, and which do not transplant readily, as melons and cucumbers, may be planted in forcing-hills in the field. One of these hills is shown in Fig. 191. The frame or mold is shown at the left. This mold is a box with flaring sides and no top or bottom, and provided with a handle. This frame is placed with the small end down at the point where the seeds are to be planted, and the earth is hilled up about it and firmly packed with the feet. The mold is then withdrawn, and a pane of glass is laid upon the top of the mound to concentrate the sun's rays, and to prevent the bank from washing down with the rains. A clod of earth or a stone may be placed upon the pane to hold it down. Sometimes a brick is used as a mold. This type of forcing-hill is not much used, because the bank of earth is liable to be washed away, and heavy rain coming when the glass is off will fill the hill with water and drown the plant. However, it can be used to very good advantage when the gardener can give it close attention.
A forcing-hill is sometimes made by digging a hole in the ground and planting the seeds in the bottom of it, placing the pane of glass upon a slight ridge or mound which is made on the surface of the ground. This method is less desirable than the other, because the seeds are placed in the poorest and coldest soil, and the hole is very likely to fill with water in the early days of spring.
An excellent type of forcing-hill is made by the use of the hand-box, as shown in Fig. 192. This is a rectangular box, without top or bottom, and a pane of glass is slipped into a groove at the top. It is really a miniature coldframe. The earth is banked up slightly about the box, in order to hold it against winds and to prevent the water from running into it. If these boxes are made of good lumber and painted, they will last for many years. Any size of glass may be used which is desired, but a ten-by-twelve pane is as good as any for general purposes.
After the plants are thoroughly established in these forcing-hills, and the weather is settled, the protection is wholly removed, and the plants grow normally in the open.
A very good temporary protection may be given to tender plants by using four panes of glass, as explained in Fig. 193, the two inner panes being held together at the top by a block of wood through which four nails are driven. Plants are more likely to burn in these glass frames than in the hand-boxes, and such frames are not so well adapted to the protection of plants in very early spring; but they are often useful for special purposes.
In all forcing-hills, as in coldframes and hotbeds, it is exceedingly important that the plants receive plenty of air on bright days. Plants that are kept too close become weak or "drawn", and lose the ability to withstand changes of weather when the protection is removed. Even though the wind is cold and raw, the plants inside the frames ordinarily will not suffer if the glass is taken off when the sun is shining.
Coldframes.
A coldframe is nothing more than an enlarged hand-box; that is, instead of protecting but a single plant or a single hill with a single pane of glass, the frame is covered with sash, and is large enough to accommodate many plants.
There are three general purposes for which a coldframe is used: For the starting of plants early in spring; for receiving partially hardened plants that have been started earlier in hotbeds and forcing-houses; for wintering young cabbages, lettuce, and other hardy plants that are sown in the fall.
Coldframes are ordinarily placed near the buildings, and the plants are transplanted into the field when settled weather comes. Sometimes, however, they are made directly in the field where the plants are to remain, and the frames, and not the plants, are removed. When used for this latter purpose, the frames are made very cheap by running two rows of parallel planks through the field at a distance apart of six feet. The plank on the north is ordinarily ten to twelve inches wide, and that on the south eight to ten inches. These planks are held in place by stakes, and the sashes are laid across them. Seeds of radishes, beets, lettuce, and the like, are then sown beneath the sash, and when settled weather arrives, the sash and planks are removed and the plants are growing naturally in the field. Half-hardy plants, as those mentioned, may be started fully two or three weeks in advance of the normal season by this means.
One of the simplest types of coldframes is shown in Fig. 194, which is a lean-to against the foundation of a house. A sill is run just above the surface of the ground, and the sashes, shown at D, are laid on rafters which run from this sill to the sill of the house, A. If this frame is on the south side of the building, plants may be started even as early as a month before the opening of the season. Such lean-to frames are sometimes made against greenhouses or warm cellars, and heat is supplied to them by the opening of a door in the wall, as at B. In frames that are in such sunny positions as these, it is exceedingly important that care be taken to remove the sash, or at least to give ample ventilation, in all sunny days.
A different type of lean-to structure is shown in Fig. 195. This may be either a temporary or permanent building, and it is generally used for the protection of half-hardy plants that are grown in pots and tubs. It may be used, however, for the purpose of forwarding pot-plants early in the spring and for protection of peaches, grapes, oranges, or other fruits in tubs or boxes. If it is desired merely to protect the plants through the winter, it is best to have the structure on the north side of the building, in order that the sun may not force the plants into activity.
Another structure that may be used both to carry half-hardy plants over winter and for starting plants early in spring is shown in Fig. 196. It is really a miniature greenhouse without heat. It is well adapted for mild climates. The picture was made from a structure in the coast region of North Carolina.
The common type of coldframe is shown in Fig. 197. It is twelve feet long and six feet wide, and is covered with four three-by-six sash. It is made of ordinary lumber loosely nailed together. If one expects to use coldframes or hotbeds every year, however, it is advisable to make the frames of two-inch stuff, well painted, and to join the parts by bolts and tenons, so that they may be taken apart and stored until needed for the next year's crop. Figure 198 suggests a method of making frames so that they may be taken apart.
It is always advisable to place coldframes and hotbeds in a protected place, and particularly to protect them from cold north winds. Buildings afford excellent protection, but the sun is sometimes too hot on the south side of large and light-colored buildings. One of the best means of protection is to plant a hedge of evergreens, as shown in Fig. 199. It is always desirable, also to place all the coldframes and hotbeds close together, for the purpose of economizing time and labor. A regular area or yard may be set aside for this purpose.
Various small and portable coldframes may be used about the garden for the protection of tender plants or to start them early in the spring. Pansies, daisies, and border carnations, for example, may be brought on very early by setting such frames over them or by planting them under the frames in the fall. These frames may be of any size desired, and the sash may be either removable, or, in case of small frames, they may be hinged at the top. Figs. 200-203 illustrate various types.
Hotbeds.
A hotbed differs from a coldframe in being provided with bottom heat. This heat is ordinarily supplied by means of fermenting manure, but it may be obtained from other fermenting material, as tanbark or leaves, or from artificial heat, as flues, steam pipes, or water pipes.
The hotbed is used for the very early starting of plants; and when the plants have outgrown the bed, or have become too thick, they are transplanted into cooler hotbeds or into coldframes. There are some crops, however, that are carried to full maturity in the hotbed itself, as radishes and lettuce.
The date at which the hotbed may be started with safety depends almost entirely on the means at command of heating it and on the skill of the operator. In the northern states, where outdoor gardening does not begin until the first or the last of May, hotbeds are sometimes started as early as January; but they are ordinarily delayed until early in March.
The heat for hotbeds is commonly supplied by the fermentation of horse manure. It is important that the manure be as uniform as possible in composition and texture, that it come from highly fed horses, and is practically of the same age. The best results are usually secured with manure from livery stables, from which it can be obtained in large quantities in a short space of time. Perhaps as much as one half of the whole material should be of litter or straw that has been used in the bedding.
The manure is placed in a long and shallow square-topped pile, not more than four or six feet high, as a rule, and is then allowed to ferment. Better results are generally obtained if the manure is piled under cover. If the weather is cold and fermentation does not start readily, wetting the pile with hot water may start it. The first fermentation is nearly always irregular; that is, it begins unequally in several places in the pile. In order to make the fermentation uniform, the pile must be turned occasionally, taking care to break up all hard lumps and to distribute the hot manure throughout the mass. It is sometimes necessary to turn the pile five or six times before it is finally used, although half this number of turnings is ordinarily sufficient. When the pile is steaming uniformly throughout, it is placed in the hotbed, and is covered with the earth in which the plants are to be grown.
Hotbed frames are sometimes set on top of the pile of fermenting manure, as shown in Fig. 204. The manure should extend some distance beyond the edges of the frame; otherwise the frame will become too cold about the outside, and the plants will suffer.
It is preferable, however, to have a pit beneath the frame in which the manure is placed. If the bed is to be started in midwinter or very early in the spring, it is advisable to make this pit in the fall and to fill it with straw or other litter to prevent the earth from freezing deep. When it is time to make the bed, the litter is thrown out, and the ground is warm and ready to receive the fermenting manure. The pit should be a foot wider on either side than the width of the frame. Fig. 205 is a cross-section of such a hotbed pit. Upon the ground a layer of an inch or two of any coarse material is placed to keep the manure off the cold earth. Upon this, from twelve to thirty inches of manure is placed. Above the manure is a thin layer of leafmold or some porous material, that will serve as a distributor of the heat, and above this is four or five inches of soft garden loam, in which the plants are to be grown.
It is advisable to place the manure in the pit in layers, each stratum to be thoroughly trodden down before another one is put in. These layers should be four to eight inches in thickness. By this means the mass is easily made uniform in consistency. Manure that has too much straw for the best results, and which will therefore soon part with its heat, will spring up quickly when the pressure of the feet is removed. Manure that has too little straw, and which therefore will not heat well or will spend its heat quickly, will pack down into a soggy mass underneath the feet. When the manure has sufficient litter, it will give a springy feeling to the feet as a person walks over it, but will not fluff up when the pressure is removed. The quantity of manure to be used will depend on its quality, and also on the season in which the hotbed is made. The earlier the bed is made, the larger should be the quantity of manure. Hotbeds that are intended to hold for two months should have about two feet of manure, as a rule.
The manure will ordinarily heat very vigorously for a few days after it is placed in the bed. A soil thermometer should be thrust through the earth down to the manure, and the frame kept tightly closed. When the temperature is passing below 90 deg., seeds of the warm plants, like tomatoes, may be sown, and when it passes below 80 deg. or 70 deg., the seeds of cooler plants may be sown.
If hotbeds are to be used every year, permanent pits should be provided for them. Pits are made from two to three feet deep, preferably the former depth, and are walled up with stone or brick. It is important that they be given good drainage from below. In the summer-time, after the sash are stripped, the old beds may be used for the growing of various delicate crops, as melons or half-hardy flowers. In this position, the plants can be protected in the fall. As already suggested, the pits should be cleaned out in the fall and filled with litter to facilitate the work of making the new bed in the winter or spring.
Various modifications of the common type of hotbed will suggest themselves to the operator. The frames should ordinarily run in parallel rows, so that a man walking between them can attend to the ventilation of two rows of sash at once. Fig. 206 shows a different arrangement. There are two parallel runs, with walks on the outside, and between them are racks to receive the sash from the adjacent frames. The sash from the left-hand bed are run to the right, and those from the right-hand bed are run to the left. Running on racks, the operator does not need to handle them, and the breakage of glass is therefore less; but this system is little used because of the difficulty of reaching the farther side of the bed from the single walk.
If the hotbed were high enough and broad enough to allow a man to work inside, we should have a forcing-house. Such a structure is shown in Fig. 207, upon one side of which the manure and soil are already in place. These manure-heated houses are often very efficient, and are a good make-shift until such time as the gardener can afford to put in flue or pipe heat.
Hotbeds may be heated by means of steam or hot water. They can be piped from the heater in a dwelling-house or greenhouse. Fig. 208 shows a hotbed with two pipes, in the positions 7, 7 beneath the bed. The earth is shown at 4, and the plants (which, in this case, are vines) are growing upon a rack, at 6. There are doors in the end of the house, shown in 2, 2, which may be used for ventilation or for admitting air underneath the beds. The pipes should not be surrounded by earth, but should run through a free air space.
It would scarcely pay to put in a hot water or steam heater for the express purpose of heating hotbeds, for if such an expense were incurred, it would be better to make a forcing-house. Hotbeds may be heated, however, with hot-air flues with very good results. A home-made brick furnace may be constructed in a pit at one end of the run and underneath a shed, and the smoke and hot air, instead of being carried directly upwards, is carried through a slightly rising horizontal pipe that runs underneath the beds. For some distance from the furnace, this flue may be made of brick or unvitrified sewer pipe, but stove-pipe may be used for the greater part of the run. The chimney is ordinarily at the farther end of the run of beds. It should be high, in order to provide a good draft. If the run of beds is long, there should be a rise in the underlying pipe of at least one foot in twenty-five. The greater the rise in this pipe, the more perfect will be the draft. If the runs are not too long, the underlying pipe may return underneath the beds and enter a chimney directly over the back end of the furnace, and such a chimney, being warmed from the furnace, will ordinarily have an excellent draft. The underlying pipe should occupy a free space or pit beneath the beds, and whenever it lies near to the floor of the bed or is very hot, it should be covered with asbestos cloth. While such flue-heated hotbeds may be eminently successful with a grower or builder of experience, it may nevertheless be said, as a general statement, that whenever such trouble and expense are incurred, it is better to make a forcing-house. The subject of forcing-houses and greenhouses is not discussed in this book.
The most satisfactory material for use in hotbed and cold-frame sash is double-thick, second-quality glass; and panes twelve inches wide are ordinarily broad enough, and they suffer comparatively little in breakage. For coldframes, however, various oiled papers and waterproof cloths may be used, particularly for plants that are started little in advance of the opening of the season. When these materials are used, it is not necessary to have expensive sash, but rectangular frames are made from strips of pine seven-eighths inch thick and two and one-half inches wide, halved together at the corners and each corner reenforced by a square carriage-corner, such as is used by carriage-makers to secure the corners of buggy boxes. These corners can be bought by the pound at hardware stores.
Management of hotbeds.
Close attention is required in the management of hotbeds, to insure that they do not become too hot when the sun comes out suddenly, and to give plenty of fresh air.
Ventilation is usually effected by raising the sash at the upper end and letting it rest upon a block. Whenever the temperature is above freezing point, it is generally advisable to take the sash off part way, as shown in the central part of Fig. 199, or even to strip it off entirely, as shown in Fig. 197.
Care should be taken not to water the plants at nightfall, especially in dull and cold weather, but to give them water in the morning, when the sun will soon bring the temperature up to its normal state. Skill and judgment in watering are of the greatest importance in the management of hotbeds; but this skill comes only from thoughtful practice. The satisfaction and effectiveness of the work are greatly increased by good hose connections and good watering-pots (Fig. 209).
Some protection, other than the glass, must be given to hotbeds. They need covering on every cold night, and sometimes during the entire day in very severe weather. Very good material for covering the sash is matting, such as is used for covering floors. Old pieces of carpet may also be used. Various hotbed mattings are sold by dealers in gardeners' supplies.
Gardeners often make mats of rye straw, although the price of good straw and the excellence of manufactured materials make this home-made matting less desirable than formerly. Such mats are thick and durable, and are rolled up in the morning, as shown in Fig. 199. There are various methods of making these straw mats, but Fig. 210 illustrates one of the best. A frame is made after the manner of a saw-horse, with a double top, and tarred or marline twine is used for securing the strands of straw. It is customary to use six runs of this warp. Twelve spools of string are provided, six hanging on either side. Some persons wind the cord upon two twenty-penny nails, as shown in the figure, these nails being held together at one end by wire which is secured in notches filed into them. The other ends of the spikes are free, and allow the string to be caught between them, thus preventing the balls from unwinding as they hang upon the frame. Two wisps of straight rye straw are secured and laid upon the frame, with the butt ends outward and the heads overlapping. Two opposite spools are then brought up, and a hard knot is tied at each point. The projecting butts of the straw are then cut off with a hatchet, and the mat is allowed to drop through to receive the next pair of wisps. In making these mats, it is essential that the rye contains no ripe grain; otherwise it attracts the mice. It is best to grow rye for this especial purpose, and to cut it before the grain is in the milk, so that the straw does not need to be threshed.
In addition to these coverings of straw or matting, it is sometimes necessary to provide board shutters to protect the beds, particularly if the plants are started very early in the season. These shutters are made of half-inch or five-eighths-inch pine lumber, and are the same size as the sash—three by six feet. They may be placed upon the sash underneath the matting, or they may be used above the matting. In some cases they are used without any matting.
In the growing of plants in hotbeds, every effort should be made to prevent the plants from growing spindling, or becoming "drawn." To make stocky plants, it is necessary to give room to each plant, to be sure that the distance from the plants to the glass is not great, to provide not too much water in dull and cold weather, and particularly to give abundance of air.
CHAPTER VI
PROTECTING PLANTS FROM THINGS THAT PREY ON THEM
Plants are preyed on by insects and fungi; and they are subject to various kinds of disease that, for the most part, are not yet understood. They are often injured also by mice and rabbits (p. 144), by moles, dogs, cats, and chickens; and fruit is eaten by birds. Moles may be troublesome on sandy land; they heave the ground by their burrowing and may often be killed by stamping when the burrow is being raised; there are mole traps that are more or less successful. Dogs and cats work injury mostly by walking across newly made gardens or lying in them. These animals, as well as chickens, should be kept within their proper place (p. 160); or if they roam at will, the garden must be inclosed in a tight wire fence or the beds protected by brush laid closely over them.
The insects and diseases that attack garden plants are legion; and yet, for the most part, they are not very difficult to combat if one is timely and thorough in his operations. These difficulties may be divided into three great categories: the injuries wrought by insects; the injuries of parasitic fungi; the various types of so-called constitutional diseases, some of which are caused by germs or bacteria, and many of which have not yet been worked out by investigators.
The diseases caused by parasitic fungi are usually distinguished by distinct marks, spots or blisters on the leaves or stems, and the gradual weakening or death of the part; and, in many cases, the leaves drop bodily. For the most part, these spots on the leaves or stems sooner or later exhibit a mildew-like or rusty appearance, due to the development of the spores or fruiting bodies. Fig. 211 illustrates the ravages of one of the parasitic fungi, the shot-hole fungus of the plum. Each spot probably represents a distinct attack of the fungus, and in this particular disease these injured parts of tissue are liable to fall out, leaving holes in the leaf. Plum leaves that are attacked early in the season by this disease usually drop prematurely; but sometimes the leaves persist, being riddled by holes at the close of the season. Fig. 212 is the rust of the hollyhock. In this case the pustules of the fungus are very definite on the under side of the leaf. The blisters of leaf-curl are shown in Fig. 213. The ragged work of apple scab fungus is shown in Fig. 214.
The constitutional and bacterial diseases usually affect the whole plant, or at least large portions of it; and the seat of attack is commonly not so much in the individual leaves as in the stems, the sources of food supply being thereby cut off from the foliage. The symptoms of this class of diseases are general weakening of plant when the disease affects the plant as a whole or when it attacks large branches; or sometimes the leaves shrivel and die about the edges or in large irregular discolored spots, but without the distinct pustular marks of the parasitic fungi. There is a general tendency for the foliage on plants affected with such diseases to shrivel and to hang on the stem for a time. One of the best illustrations of this type of disease is the pear-blight. Sometimes the plant gives rise to abnormal growths, as in the "willow shoots" of peaches affected with yellows (Fig. 215).
Another class of diseases are the root-galls. They are of various kinds. The root-gall of raspberries, crown-gall of peaches, apples, and other trees, is the most popularly recognized of this class of troubles (Fig. 216). It has long been known as a disease of nursery stock. Many states have laws against the sale of trees showing this disease. Its cause was unknown, until in 1907 Smith and Townsend, of the Bureau of Plant Industry, United States Department of Agriculture, undertook an investigation. They proved that it is a bacterial disease (caused by Bacterium tumefaciens); but just how the bacteria gain entrance to the root is not known. The same bacterium may cause galls on the stems of other plants, as, for example, on certain of the daisies. The "hairy-root" of apples, and certain galls that often appear on the limbs of large apple-trees, are also known to be caused by this same bacterium. The disease seems to be most serious and destructive on the raspberry, particularly the Cuthbert variety. The best thing to be done when the raspberry patch becomes infested is to root out the plants and destroy them, planting a new patch with clean stock on land that has not grown berries for some time. Notwithstanding the laws that have been made against the distribution of root-gall from nurseries, the evidence seems to show that it is not a serious disease of apples or peaches, at least not in the northeastern United States. It is not determined how far it may injure such trees.
Of obvious insect injuries, there are two general types,—those wrought by insects that bite or chew their food, as the ordinary beetles and worms, and those wrought by insects that puncture the surface of the plant and derive their food by sucking the juices, as scale-insects and plant-lice. The canker-worm (Fig. 217) is a notable example of the former class; and many of these insects may be dispatched by the application of poison to the parts that they eat. It is apparent, however, that insects which suck the juice of the plant are not poisoned by any liquid that may be applied to the surface. They may be killed by various materials that act upon them externally, as the soap washes, miscible oils, kerosene emulsions, lime-and-sulfur sprays, and the like.
There has been much activity in recent years in the identification and study of insects, fungi, and microorganisms that injure plants; and great numbers of bulletins and monographs have been published; and yet the gardener who has tried assiduously to follow these investigations is likely to go to his garden any morning and find troubles that he cannot identify and which perhaps even an investigator himself might not understand. It is important, therefore, that the gardener inform himself not only on particular kinds of insects and diseases, but that he develop a resourcefulness of his own. He should be able to do something, even if he does not know a complete remedy or specific. Some of the procedure, preventive and remedial, that needs always to be considered, is as follows:—
Keep the place clean, and free from infection. Next to keeping the plants vigorous and strong, this is the first and best means of averting trouble from insects and fungi. Rubbish and all places in which the insects can hibernate and the fungi can propagate should be done away with. All fallen leaves from plants that have been attacked by fungi should be raked up and burned, and in the fall all diseased wood should be cut out and destroyed. It is important that diseased plants are not thrown on the manure heap, to be distributed through the garden the following season.
Practice a rotation or alternation of crops (p. 114). Some of the diseases remain in the soil and attack the plant year after year. Whenever any crop shows signs of root disease, or soil disease, it is particularly important that another crop be grown on the place.
See that the disease or insect is not bred on weeds or other plants that are botanically related to the crop you grow. If the wild mallow, or plant known to children as "cheeses" (Malva rotundifolia), is destroyed, there will be much less difficulty with hollyhock rust. Do not let the cabbage club-root disease breed on wild turnips and other mustards, or black-knot on plum sprouts and wild cherries, or tent-caterpillars on wild cherries and other trees.
Always be ready to resort to hand-picking. We have grown so accustomed to killing insects by other means that we have almost forgotten that hand-picking is often the surest and sometimes even the most expeditious means of checking an invasion in a home garden. Many insects can be jarred off early in the morning. Egg-masses on leaves and stems may be removed. Cutworms may be dug out. Diseased leaves may be picked off and burned; this will do much to combat the hollyhock rust, aster rust, and other infections.
Keep close watch on the plants, and be prepared to strike quickly. It should be a matter of pride to a gardener to have in his workhouse a supply of the common insecticides and fungicides (Paris green or arsenate of lead, some of the tobacco preparations, white hellebore, whale-oil soap, bordeaux mixture, flowers of sulfur, carbonate of Copper for solution in ammonia), and also a good hand syringe (Fig. 218), a knapsack pump (Figs. 219, 220), a bucket pump (Figs. 221, 222), a hand bellows or powder gun, perhaps a barrow outfit (Figs. 223, 224, 225), and if the plantation is large enough, some kind of a force pump (Figs. 226, 227, 228). If one is always ready, there is little danger from any insect or disease that is controllable by spraying.
Screens and covers.
There are various ways of keeping insects away from plants. One of the best is to cover the plants with fine mosquito-netting or to grow them in hand-frames, or to use a wire-covered box like that shown in Fig. 229. In growing plants under such covers, care must be taken that the plants are not kept too close or confined; and in cases in which the insects hibernate in the soil, these boxes, by keeping the soil warm, may cause the insects to hatch all the sooner. In most cases, however, these covers are very efficient, especially for keeping the striped bugs off young plants of melons and cucumbers.
Cut-worms may be kept away from plants by placing sheets of tin or of heavy glazed paper about the stem of the plant, as shown in Fig. 230. Climbing cut-worms are kept off young trees by the means shown in Fig. 231. Or a roll of cotton may be placed about the trunk of the tree, a string being tied on the lower edge of the roll and the upper edge of the cotton turned down like the top of a boot; the insects cannot crawl over this obstruction (p. 203).
The maggots that attack the roots of cabbages and cauliflowers may be kept from the plant by pieces of tarred paper, which are placed close about the stem upon the surface of the ground. Fig. 232 illustrates a hexagon of paper, and also shows a tool used for cutting it. This means of preventing the attacks of the cabbage maggot is described in detail by the late Professor Goff (for another method of controlling cabbage maggot see p. 201):—
"The cards are cut in a hexagonal form, in order better to economize the material, and a thinner grade of tarred paper than the ordinary roofing felt is used, as it is not only cheaper, but being more flexible, the cards made from it are more readily placed about the plant without being torn. The blade of the tool, which should be made by an expert blacksmith, is formed from a band of steel, bent in the form of a half hexagon, and then taking an acute angle, reaches nearly to the center, as shown in Fig. 232. The part making the star-shaped cut is formed from a separate piece of steel, so attached to the handle as to make a close joint with the blade. The latter is beveled from the outside all round, so that by removing the part making the star-shaped cut, the edge may be ground on a grindstone. It is important that the angles in the blade be made perfect, and that its outline represents an exact half hexagon. To use the tool, place the tarred paper on the end of a section of a log or piece of timber and first cut the lower edge into notches, as indicated at a, Fig. 232, using only one angle of the tool. Then commence at the left side and place the blade as indicated by the dotted lines, and strike at the end of the handle with a light mallet, and a complete card is made. Continue in this manner across the paper. The first cut of every alternate course will make an imperfect card, and the last cut in any course may be imperfect, but the other cuts will make perfect cards if the tool is correctly made, and properly used. The cards should be placed about the plants at the time of transplanting. To place the card, bend it slightly to open the slit, then slip it on to the center, the stem entering the slit, after which spread the card out flat, and press the points formed by the star-shaped cut snugly around the stem."
Fumigating.
An effective means of destroying insects in glass houses is by fumigating with various kinds of smoke or vapors. The best material to use for general purposes is some form of tobacco or tobacco compounds. The old method of fumigating with tobacco is to burn slowly slightly dampened tobacco stems in a kettle or scuttle, allowing the house to be filled with the pungent smoke. Lately, however, fluid extracts and other preparations of tobacco have been brought into use, and these are so effective that the tobacco-stem method is becoming obsolete. The use of hydrocyanic acid gas in greenhouses is now coming to be common, for plant-lice, white-fly, and other insects. It is also used to fumigate nursery stock for San Jose scale, and mills and dwellings for such pests and vermin as become established in them. The following directions are from Cornell Bulletin 252 (from which the formulas in the succeeding pages, and most of the advice, are also taken):—
"No general formula can be given for fumigating the different kinds of plants grown in greenhouses, as the species and varieties differ greatly in their ability to withstand the effects of the gas. Ferns and roses are very susceptible to injury, and fumigation if attempted at all should be performed with great caution. Fumigation will not kill insect eggs and thus must be repeated when the new brood appears. Fumigate only at night when there is no wind. Have the house as dry as possible and the temperature as near 60 deg. as practicable.
"Hydrocyanic acid gas is a deadly poison, and the greatest care is required in its use. Always use 98 to 100 per cent pure potassium cyanide and a good grade of commercial sulfuric acid. The chemicals are always combined in the following proportion: Potassium cyanide, 1 oz.; sulfuric acid, 2 fluid oz.; water, 4 fluid oz. Always use an earthen dish, pour in the water first, and add the sulfuric acid to it. Put the required amount of cyanide in a thin paper bag and when all is ready, drop it into the liquid and leave the room immediately. For mills and dwellings, use 1 oz. of cyanide for every 100 cu. ft. of space. Make the doors and windows as tight as possible by pasting strips of paper over the cracks. Remove the silverware and food, and if brass and nickel work cannot be removed, cover with vaseline. Place the proper amount of the acid and water for every room in 2-gal. jars. Use two or more in large rooms or halls. Weigh out the potassium cyanide in paper bags, and place them near the jars. When all is ready, drop the cyanide into the jars, beginning on the top floors, since the fumes are lighter than air. In large buildings, it is frequently necessary to suspend the bags of cyanide over the jars by cords running through screw eyes and all leading to a place near the door. By cutting all the cords at once the cyanide will be lowered into the jars and the operator may escape without injury. Let the fumigation continue all night, locking all outside doors and placing danger signs on the house."
In greenhouses, the white-fly on cucumbers and tomatoes may be killed by overnight fumigation with 1 oz. of potassium cyanide to every 1000 cu. ft. of space; or with a kerosene emulsion spray or whale-oil soap, on plants not injured by these materials.
The green aphis is dispatched in houses by fumigation with any of the tobacco preparations; on violets, by fumigation with 1/2 to 3/4 oz. potassium cyanide for every 1000 cu. ft. of space, leaving the gas in from 1/2 to 1 hr.
The black aphis is more difficult to kill than the green aphis, but may be controlled by the same methods thoroughly used.
Soaking tubers and seeds.
Potato scab may be prevented, so far as planting infected "seed" is concerned, by soaking the seed tubers for half an hour in 30 gal. of water containing 1 pt. of commercial (about 40 per cent) formalin. Oats and wheat, when attacked by certain kinds of smut, may be rendered safe to sow by soaking for ten minutes in a similar solution. It is probable that some other tubers and seeds can be similarly treated with good results.
Potatoes may also be soaked (for scab) one and one-half hours in a solution of corrosive sublimate, 1 oz. to 7 gal. of water.
Spraying.
The most effective means of destroying insects and fungi however, in any general or large way, is by the use of various sprays. The two general types of insecticides have already been mentioned—those that kill by poisoning, and those that kill by destroying the body of the insect. Of the former, there are three materials in common use—Paris green, arsenate of lead, and hellebore. Of the latter, the most usual at present are kerosene emulsion, miscible oils, and the lime-sulfur wash.
Sprays for fungi usually depend for their efficiency on some form of copper or sulfur, or both. For surface mildews, as grape mildew, dusting flowers of sulfur on the foliage is a protection. In most cases, however, it is necessary to apply materials in liquid form, because they can be more thoroughly and economically distributed, and they adhere to the foliage better. The best general fungicide is the bordeaux mixture. It is generally, however, not advisable to use the bordeaux mixture on ornamental plants, because it discolors the foliage and makes the plants look very untidy. In such cases it is best to use the ammoniacal copper solution, which leaves no stain.
In all spraying operations it is especially important that the applications be made the very moment the insect or disease is discovered, or in the case of fungous diseases, if one is expecting an attack, it is well to make an application of bordeaux mixture even before the disease appears. When the fungus once gets inside the plant tissue, it is very difficult to destroy it, inasmuch as fungicides act on these deep-seated fungi very largely by preventing their fruiting and their further spread on the surface of the leaf. For ordinary conditions, from two to four sprayings are necessary to dispatch the enemy. In spraying for insects in home gardens, it is often advisable to make a second application the day following the first one in order to destroy the remaining insects before they recover from the first treatment.
There are many kinds of machines and devices for the application of sprays to plants. For a few individual specimens, the spray may be applied with a whisk, or with a common garden syringe. If one has a few trees to treat, however, it is best to have some kind of bucket pump like those shown in Figs. 221, 222. On a lawn or in a small garden a tank on wheels (Figs. 223, 224, 225) is handy and efficient. In such cases, or even for larger areas, some of the knapsack pumps (Figs. 219, 220) are very desirable. These machines are always serviceable, because the operator stands so near to his work; but as they carry a comparatively small quantity of liquid and do not throw it rapidly, they are expensive when much work is to be done. Yet, in ordinary home grounds, the knapsack pump or compressed-air pump is one of the most efficient and practicable of all the spraying devices.
For large areas, as for small orchards and fields, a barrel pump mounted on a wagon is best. Common types of barrel pumps are shown in Figs. 226, 227, 228. Commercial plantations are now sprayed by power machines. There are many good patterns of spraying machines, and the intending purchaser should send for catalogues to the various manufacturers. The addresses may be found in the advertising pages of rural papers. |
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