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Fig. 37. Chauvière’s Propagating-oven.

Fig. 38. Lecoq’s Propagating-oven.

Fig. 39. Barnard’s Propagating-tank.

Barnard’s propagating-tank, Fig. 39, is a practicable device for attachment to a common stove. A similar apparatus may be attached to the pipes of a greenhouse. The tank consists of a long wooden box made of matched boards, and put together with paint between the joints to make the box water-tight. The box should be about three feet wide and ten inches deep, and may be from ten to thirty feet long, according to the space required. In the middle of the box is a partition, extending nearly the whole length of the box, and on the inside, on each side, is a ledge or piece of moulding to support slates to be laid over the entire surface of the box. The slates are supported by the ledges and by the central partition, and should be fastened down with cement to prevent the propagating sand from falling into the tank. One slate is left out near the end, next the fire, to enable the operator to see the water and to keep it at the right level. On the slates sand is spread, in which the cuttings may be struck, the sand nearly filling the box. At one end of the box is placed a common cylinder stove, with pipe to the chimney. Inside the stove is a lead or iron pipe (iron is the best) bent in a spiral. This coil, which is directly in the fire, is connected by iron pipes with the tank, one pipe leading to one side of the partition and the other to the opposite side, as shown in the drawing. If water is placed in the tank it will fill the pipes and form a continuous circulating system through the pipes and up one side of the box past the end of the partition, and down the other side. A fire in the stove causes the water to circulate through the tank and impart to the bed a genial warmth.

Fig. 40. Zinc Propagating-tank.

There are various tanks designed to rest upon the pipes in a greenhouse. The principle of their construction is essentially the same as of those described in previous pages—bottom heat, a tray of water, and a bed of soil. Earthenware tanks are commonly employed, but a recent English device, Fig. 40, is made of zinc. It is about seven inches deep, and holds an inch or two of water in the bottom. A tray five inches deep sets into the tank. The water is supplied through a funnel at the base.

Cuttings usually “strike” better when they touch the side of the pot than when they are wholly surrounded by soil. This is because the earthenware allows greater uniformity in moisture than the earth, and supplies air and a mild bottom heat. Various devices are employed for the purpose of securing these advantages to the best effect. These are usually double pots, in one of which water is placed. A good method is that represented in Fig. 41, which shows a pot, b, plugged with plaster of Paris at the bottom, placed inside a larger one. The earth is placed between the two, drainage material occupying the bottom, a, and fine soil the top, c. Water stands in the inner pot as high as the dotted line and feeds uniformly into the surrounding soil. The positions of the water and soil are frequently reversed, but in that case there is less space available for cuttings. Neumann’s cutting-pot is shown in Fig. 42. This contains an inverted pot in the center, a, designed to supply drainage and to admit heat into the center of the mass of soil.

Fig. 41. Forsyth’s Cutting-pot.

Some kind of protection, commonly combined with bottom heat, is always given cuttings made from the soft and growing parts. In in-door work, any of the devices named above may be employed, but a box like that shown in Fig. 32 is one of the most useful for common operations. Or the greenhouse itself may afford sufficient protection, especially if the cuttings are shaded when first set to check evaporation from the plant and soil, and to prevent too great heat. This shading is usually supplied by whitewashing the glass, or a newspaper may be laid over the cutting bed for a few days. A greenhouse table or bench prepared for the growing of cuttings is known as a “cutting bench.” If the cuttings become too dry or too hot, they will wilt or “flag.” In out-door work soft cuttings are usually placed in an ordinary cold-frame, and these frames must be shaded. They may be placed under trees or on the shady side of a building, or if they are numerous, as in commercial establishments, a cloth screen should be provided as shown in Fig. 5, page 13.

Fig. 42. Neumann’s Cutting-pot.

Soils and General Methods.—Soil for all cuttings should be well-drained. It should not be so compact as to hold a great quantity of water, nor should it be so loose as to dry out very quickly. It should not “bake” or form a crust on its surface. As a rule, especially for cuttings made of growing parts, the soil should not contain vegetable matter, as such material holds too much water and it is often directly injurious to the cutting. A coarse sharp, clean sand is the best material for use in-doors. Very fine sand packs too hard, and should not be used. Some propagators prefer to use fine gravel, composed of particles from an eighth to a fourth of an inch in diameter, and from which all fine material has been washed. This answers well for green cuttings if a propagating-frame is used to check evaporation and attention is given to watering, because drainage is so perfect and the material so quickly permeable that uniformity of treatment is secured. Damping-off is less liable to occur in such material than in denser soils. The same advantages are to some extent present in sphagnum moss and cocoanut fibre, both of which are sometimes used in place of earth. The “silver sand” used by florists is a very clean and white sand which derives its particular advantages from the almost entire absence of any vegetable matter. But it is not now considered so essential to successful propagation as it was formerly, and fully as good material may often be found in a common sand-bank. Cuttings which strike strongly and vigorously may be placed in a soil made of light garden loam with twice its bulk of sand added to it. All soils used for in-door cuttage should be sifted or screened before using to bring them to a uniform texture.

Hard-wood cuttings are commonly planted out-doors in mellow and light loam, well trenched. Only fine and well-rotted manure should be applied to the cutting bed, and it should be well mixed with the soil. In most cases, a well-drained soil gives best results, but some cuttings root and grow well in wet soils or even in standing water, as poplars, willows, some of the dogwoods, plane-tree and others.

Bottom heat is always essential to the best success with cuttings. In out-door work this is supplied by the natural heat of the soil in spring and summer, and it is often intensified by burying hard-wooded cuttings bottom end up for a time before planting them. This operation of inverting cuttings is often practiced with grapes, particularly with the Delaware and others which root with some difficulty. The cuttings are tied in bundles and are buried in a sandy place, with the tops down, the butts being covered two or three inches with sand. They may be put in this position in the fall and allowed to remain until the ground begins to freeze hard, or they may be buried in spring and allowed to remain until May or June and then be regularly planted. In out-door cuttage, the cuttings which are of medium length, from six to eight inches, derive more bottom heat than the very long ones, such as were formerly used for the propagation of the grape. In in-door work bottom heat is obtained artificially. Cutting benches should have abundant piping beneath, and in the case of many tropical and sub-tropical species the bottom heat may be intensified by enclosing the benches below so that no heat can escape into the house. Doors can be placed in the partition alongside the walk to serve as ventilators if the heat should become too intense. In all cuttings, bottom or root growth should precede top growth, and this is aided by bottom heat.

Fig. 43. Grape cutting.

As a rule, roots arise most readily from a joint, and it is therefore a common practice to cut off the base of the cutting just below a bud, as shown in the grape cutting, Fig. 43. Sometimes the cutting is severed at its point of attachment to the parent branch, and a small portion, or “heel,” of that branch is allowed to remain on the cutting. This heel may be nothing more than the curved and hardened base of the cutting at its point of attachment, as in the cornus cutting, Fig. 44. Sometimes an entire section of the parent branch is removed with the cutting, as in the “mallet” cuttings of grapes, Fig. 45. Of course, comparatively few heel or mallet cuttings can be made from a plant, as only one cutting is obtained from a branch, and it is advisable, therefore, to “cut to buds” rather than “cut to heels;” yet there are many plants which demand a heel, if satisfactory results are to be obtained. The requirements of the different species in this direction can be learned only by experience, but it may be said that in general the hardest or closest wooded plants require a heel or a joint at the base. Willows, currants, basswoods, and others with like soft wood, emit roots readily between the buds, yet even in these cases propagators quite usually cut to buds.

Fig. 44. Heel cutting of Cornus.

Wounds upon plants begin to heal by the formation of loose cellular matter which gives rise to a mass of tissue known as a callus. This tissue eventually covers the entire wound, if complete healing results. As a rule, the first apparent change in a cutting is the formation of a callus upon the lower end, and it is commonly supposed that this process must be well progressed before roots can form. But roots do not necessarily arise from the callus, and in many plants they appear to bear no relation to it in position. In willows, for instance, roots arise from the bark quite irregularly and at some distance from the callus. Yet, as a matter of practice, best results are obtained from callused cuttings, particularly if the cuttings are made from mature wood, but this is probably due quite as much to the fact that considerable time is required for the formation of the adventitious buds which give rise to the roots as from any connection between the callusing and rooting processes themselves. Hard-wood cuttings give better results when kept dormant for some time after they are cut. They are usually made in the fall, and stored during the winter in sand, sawdust or moss in a cool cellar, or buried in a sandy and well-drained place. This, at least, is the practice with hard-wood cuttings of deciduous plants. Hard-wood evergreen cuttings, when taken in the fall, are usually set at once, as their foliage will not allow them to be buried with safety; but in this case, the cuttings are kept “quiet” or dormant for a time, to allow callusing to progress. If cuttings are buried so deep that they cannot sprout, callusing may be hastened by placing them in a mild temperature. Single-eye grape cuttings are sometimes packed between layers of sand in a barrel and the barrel is set under a forcing-house bench where the temperature is about 50°. Eight or ten inches of sand is usually placed over the top layer. In this manner, cuttings which have been obtained in winter or spring can be callused before planting time.

Fig. 45. Mallet cutting of grape.

It is a singular fact that the lower end of the cutting, as it stood upon the parent plant, produces roots and the upper end produces leaves and shoots, even if the cutting is inverted. And if the cutting is divided into several parts, each part will still exhibit this same differentiation of function. This is true even of root-cuttings, and of other cuttings which possess no buds. The reasons for this localization of function are not yet clearly understood, although the phenomenon has lately been the subject of study. Upon this fact depends the hastening of the rooting process in inverted cuttings by the direct application of heat to the bottoms, and it likewise indicates that care must be taken to plant cuttings in approximately their natural direction if straight and handsome plants are desired.

The particular method of making the cutting and the treatment to which it should be subjected, must be determined for each species or genus. Some plants, as many maples, can be propagated from wood two or three years old, but in most cases the wood of the previous or present season’s growth is required. Nearly all soft and loose wooded plants grow readily from hard-wood cuttings, while those with dense wood are often multiplied more easily from soft or growing wood. Some plants, as oaks and hickories, are propagated from cuttings of any description only with great difficulty. It is probable, however, that all plants can be multiplied by cuttings if properly treated. It often happens that one or two species of a closely defined genus will propagate readily from cuttings while the other species will not, so that the propagator comes to learn by experience that different treatment is profitable for very closely related plants. For instance, most of the viburnums are propagated from layers in commercial establishments, but V. plicatum is grown extensively from cuttings.

Particular Methods—Kinds of Cuttings.—Cuttings are made from all parts of the plant. In its lowest terms, cuttage is a division of the plant itself into two or more nearly equal parts, as in the division of crowns of rhubarb, dicentra, and most other plants which tend to form broad masses or stools. This species of cuttage is at times indistinguishable from separation, as in the dividing of lily bulbs (page 25), and at other times it is essentially the same as layerage, as in the dividing of stools which have arisen from suckers or layers. This breaking or cutting up of the plants into two or more large parts which are already rooted is technically known as division. It is only necessary, in dividing plants, to see that one or more buds or shoots remain upon the portions, and these portions are then treated in the same manner as independent mature plants; or sometimes, when the divisions are small and weak, they may be handled for a time in a frame or forcing-house in the same manner as ordinary cuttings.

Cuttings proper may be divided into four general classes: 1, of tubers; 2, of roots and root-stocks; 3, of stems; 4, of leaves.

1. Tuber Cuttings.—Tubers are thickened portions of either roots or stems, and tuber cuttings therefore fall logically under classes 2 and 3; but they are so unlike ordinary cuttings that a separate classification is desirable. Tubers are stored with starch, which is designed to support or supply the plant in time of need. Tuber cuttings are therefore able to support themselves for a time if they are placed in conditions suited to their vegetation. Roots rarely arise from the tubers themselves, but from the base of the young shoots which spring from them. This fact is familiarly illustrated in the cuttings of Irish and sweet potatoes. The young sprouts can be removed and planted separately and others will arise from the tuber to take their places. This practice is employed sometimes with new or scarce varieties of the Irish potato, and three or four crops of rooted sprouts can be obtained from one tuber. The tuber is cut in two lengthwise and is then laid in damp moss or loose earth with the cut surface down, and as soon as the sprouts throw out roots sufficient to maintain them they are severed and potted off. Sweet potatoes are nearly always propagated in this manner.

In making tuber cuttings, at least one eye or bud is left to each piece, if eyes are present; but in root-tubers, like the sweet potato, there are no buds, and it is only necessary to leave upon each portion a piece of the epidermis from which adventitious buds may develop. The pseudo-bulbs of some orchids are treated in this manner, or the whole bulb is sometimes planted. A shoot, usually termed an off-shoot, arises from each pseudo-bulb or each piece of it, and this is potted off as an independent plant. (See Orchids, in Chapter VI.)

Cuttings made from the ordinary stems of some tuberiferous plants will produce tubers instead of plants. This is the case sometimes with the potato. The cutting produces a small tuber near its lower extremity, or sometimes in the axil of a leaf above ground, and this tuber must be planted to secure a new plant. Leaf cuttings of some tuberiferous or bulbiferous plants produce little tubers or bulbs in the same way. Hyacinth leaves, inserted in sand in a frame, will soon produce little bulblets at their base, and these can be removed and planted in the same manner as the bulbels described in Chapter II.

Many tubers or tuber-like portions, which possess a very moist or soft interior and a hard or close covering, vegetate more satisfactorily if allowed to dry for a time before planting. The pseudo-bulbs of orchids, crowns of pine-apples and cuttings of cactuses are examples. Portions of cactuses and pine-apples are sometimes allowed to lie in the sun from two to four weeks before planting. This treatment dissipates the excessive moisture and induces the formation of adventitious buds.

Fig. 46. Root-cutting of Blackberry.

Fig. 47. Root-cutting of Dracæna.

2. Root Cuttings.—Many plants can be multiplied with ease by means of short cuttings of the roots, particularly all species which posses a natural tendency to “sucker” or send up sprouts from the root. All root-stocks or underground stems can be made into cuttings. True root cuttings possess no buds whatever; the buds develop after the cutting is planted. Roots are cut into pieces from one to three inches long and are planted horizontally in soil or moss. These cuttings thrive best with bottom heat, but blackberries and some other plants, grow readily with ordinary out-door treatment. A root-cutting of the blackberry is shown in Fig. 46. (See Blackberry, in Chapter VI.) A growing dracæna cutting is exhibited in Fig. 47. The cuttings of this plant are handled in a propagating-frame or on a cutting bench in a warm greenhouse. The bouvardias and many other plants can be grown in the same manner. Many of the fruit-trees, as peach, cherry, apple and pear, can be grown readily from these short root-cuttings in a frame. Variegation cannot always be transmitted by root-cutting, e.g., Symphytum asperrimum, variegatum. Among kitchen garden plants, the horse-radish is the most familiar example of propagation by root-cuttings. The small side roots, a fourth inch or so in diameter, are removed when the horse-radish is dug in fall or spring, and are cut into four to six inch lengths, as seen in Fig. 48. These cuttings are known as “sets” among gardeners. (See Horse-radish, Chapter VI.) When the crowns of horse-radish are cut and used for propagation, the operation falls strictly under division, from the fact that buds or eyes are present; and the same remark applies to rhubarb, which, however, is not propagated by true root-cuttings.

Fig. 48. Horse-radish root-cuttings.

3. Stem Cuttings.—Cuttings of the stem divide themselves into two general classes: those known as cutting of the ripe, mature or hard wood, and cuttings of the green, immature or soft wood. The two classes run into each other; no hard and fast lines can be drawn.

Hard-wood cuttings are made at any time from late summer to spring. It is advisable to make them in the fall in order to allow them to callus before the planting season, and to forestall injury which might result to the parent plant from a severe winter. They may be taken as early as August, or as soon as the wood is mature, and be stripped of leaves. Callusing can then take place in time to allow of fall planting. Or the cuttings taken in early fall may be planted immediately and be allowed to callus where they stand. All fall cutting beds should be mulched to prevent the heaving of the cuttings. As a rule, however, hard-wood cuttings are buried on a sandy knoll or are stored in moss, sand or sawdust in a cellar until spring. (See page 50.)

There is no general rule to govern the length of hard-wood cuttings. Most propagators prefer to make them six to ten inches long, as this is a convenient length to handle. Two buds are always to be taken, one bud or one pair at the top and also at the bottom, but in “short-jointed” plants more are obtained. Sometimes all but the top buds are removed to prevent the appearance of too many shoots. Grape cuttings are now commonly cut to two or three buds (Fig. 43), two being the favorite number for most varieties. (See Grape, Chapter VI.) Currant and gooseberry cuttings (Fig. 49) usually bear from six to ten buds. All long hard-wood cuttings are set perpendicularly, or nearly so, and only one or two buds are allowed to stand above the surface.

Fig. 49. Currant cutting.

When the stock is rare, cuttings are made of single eyes or buds. This is particularly the case with the grape (see Chapter VI), and currants and many other plants are occasionally grown in the same manner. Fig. 50 shows a single eye grape cutting. These cuttings, whatever the species, are commonly started under glass with bottom heat, either upon a cutting bench or in a hot-bed. The soil should be kept uniformly moist, and when the leaves appear the plants should be frequently sprinkled. In from thirty to forty days the plants are ready to pot off. Single eye cuttings are usually started about three or four months before the season is fit for out-door planting, or about February in the northern states. The most advisable method of treatment varies with the season and locality as well as with the species or variety. It is well known, for instance, that the Delaware grape can be propagated more easily in some regions than in others. A common style of single eye cutting is made with the eye close to the top end, and a naked base of an inch or two. This is inserted into the soil perpendicularly, with the eye just above the surface. It is much used for a variety of plants.

Fig. 50. Single-eye Grape cutting.

Many coniferous plants are increased by cuttings on a large scale, especially retinosporas, arbor-vitæs, and the like. Cuttings are made of the mature wood, which is planted at once (in autumn) in sand under cover, usually in a cool greenhouse. Most of the species root slowly and they often remain in the original flats or benches a year, but their treatment is usually simple. In some cases junipers, yews and Cryptomeria Japonica will not make roots for nearly twelve months, keeping in good foliage however, and ultimately giving good plants. (For more explicit directions, see Thuya and Retinospora in Chapter VI.)

Most remarkable instances of propagation by means of portions of stems are on record. Chips from a tree trunk have been known to produce plants, and the olive is readily increased by knots or excrescences formed upon the trunks of old trees. These excrescences occur in many plants and are known as knaurs. They are often abundant about the base of large plane-trees. But they are not often used for purposes of propagation. Whole trunks will sometimes grow after having been cut for many months, especially of such plants as cactuses, many euphorbias and yuccas. And sections of these spongy trunks will grow, also. Even saw-logs of our common trees, as elm and ash, will sprout while in the “boom,” or water.

Green-wood cuttings are more commonly employed than those from the mature wood, as they “strike” more quickly, they can be handled under glass in the winter, and more species can be propagated by them than by hard-wood cuttings. “Slips” are green-wooded cuttings, but the term is often restricted to designate those which are made by pulling or “slipping” off a small side shoot. All soft-wooded plants and many ornamental shrubs are increased by green cuttings. There are two general classes of green-wood cuttings: those made from the soft and still growing wood, and those made from the nearly ripened green-wood, as in Azalea Indica, oleander, ficus, etc. House plants, as geraniums, coleuses, carnations, fuchsias, and the like, are grown from the soft young wood, and many harder-wooded plants are grown in the same way. Sometimes truly hard wood is used, as in camellia.

Fig. 51. Tough and brittle wood.

In making cuttings from soft and growing shoots, the first thing to learn is the proper texture or age of shoot. A very soft and flabby cutting does not grow readily, or if it does it is particularly liable to damp-off, and it usually makes a weak plant. Too old wood is slow to root, makes a poor plant and is handled with difficulty in many species. The ordinary test for beginners is the manner in which the shoot breaks. If, upon being bent, the shoot snaps off squarely so as to hang together with only a bit of bark, as in the upper break in Fig. 51, it is in the proper condition for cuttings; but if it bends or simply crushes, as in the lower portion of the figure, it is either too old or too young for good results. The tips of the shoots of soft-wooded plants are usually employed, and all or a portion of the leaves are allowed to remain. They are inserted in sharp sand to a sufficient depth to hold them in place, and the atmosphere and soil must be kept moist to prevent wilting or "flagging". The cuttings should also be shaded for the first week or two. A propagating-frame is often employed. Soft cuttings are commonly cut below a bud or cut to a heel, but this is unnecessary in easily rooted plants like geranium, coleus, heliotrope, etc. Fig. 52 shows an oleander cutting at a, a carnation at b, and a geranium at c. A coleus cutting is illustrated in Fig. 53. Sometimes the growth is so short or the stock so scarce that the cutting cannot be made long enough to hold itself in the soil. In such case a toothpick or splinter is tied to the cutting to hold it erect, as in the cactus cutting, Fig. 54, or the geranium cutting, Fig. 55. In the window garden, soft cuttings may be started in a deep plate which is filled half or two-thirds full of sand and is then filled to the brim with water, and not shaded; this method, practiced on a larger scale, is sometimes useful during the hot summer months. If bottom heat is desired, the plate may be set upon the back part of the kitchen stove. Oleanders usually root best when mature shoots are placed in bottles of water.

Fig. 52. Soft cuttings.

Fig. 53. Coleus cutting.

Cuttings from the nearly mature green-wood are employed for hard-wooded trees and shrubs, as diervillas (weigela), roses, hydrangeas, lilacs, etc. They are cut in essentially the same manner as the hard-wood cuttings described on page 55. They are often taken in summer when the buds have developed and the wood has about attained its growth. They are cut to two to four or five buds and are planted an inch or two deep in shaded frames. They are kept close for some days after setting, and the tops are sprinkled frequently. Care must be taken not to set them too deep; they are rarely put in over an inch, if the cutting is six or seven inches long. “June stock cuttings” are sometimes advantageously made; here the young shoots of hardy shrubs are taken, when about two to three inches long, the leaves partly removed, and they are planted under glass, precisely as the geranium is treated in the autumn. Several weeks are required for rooting, but good plants are obtained which, when wintered in a cold-frame, can be planted out in beds the next spring. Great care must be given to shading and watering. Hydrangea paniculata var. grandiflora, and Akebia quinata are examples; or any deutzia or more easily handled plant of which stock is scarce may be cited.

Fig. 54. Cactus cutting held by splinter.

Part of the leaves are removed, as a rule, before the cuttings are set, as shown in the rose cutting, Fig. 56, and the hydrangea cutting, Fig. 57. This is not essential, however, but it lessens evaporation and the tendency to “flag” or wilt. In most species the top can be cut off the cutting, as seen in Figs. 44 and 57, but in other cases it seriously injures the cutting. Fig. 58 shows a weigela cutting from which the top was clipped. An unusually large callus formed at the bottom, but the leaves shrivelled and the cutting is dead. This frequently occurs in what some nurserymen call “end growers,” among which may be mentioned weigelas (properly diervillas), the shrubby altheas, Cercis Japonica, and such spireas as S. cratægifolia, S. rotundifolia var. alba and S. Cantonensis (S. Reevesii of the trade) var. robusta.

Fig. 55. Cutting held by toothpick.

Fig. 56. Rose cutting.

These hardened cuttings, about two inches long, are often made in the winter from forced plants. This is particularly the case with roses (which see in Chapter VI). Cuttings taken in February, in the north, will be ready to transfer to borders or nursery beds when spring opens. Stout, well-rooted stock-plants are used from which to obtain these cuttings, and they are cut back when taken to the house in the fall in order to induce a good growth. Many hardy shrubs can be easily propagated in this way when the work is difficult in the open air, e.g., Spiræa Cantonensis (S. Reevesii of the catalogues) and S. Van Houttii. Stock plants of the soft species, like coleus, lantanas and geraniums, are obtained in like manner.

Fig. 57. Hydrangea cutting.

4. Leaf Cuttings.—Many thick and heavy leaves may be used as cuttings. Leaf cuttings are most commonly employed in the showy-leaved begonias, in succulents, and in gloxinias, but many plants can be propagated by them. Even the cabbage can be made to grow from leaf cuttings. The whole leaf may be used, as shown in Fig. 59. It is simply laid upon moist sand in a frame and held down by splinters thrust through the ribs. The wound made by the peg induces the formation of roots and a young plant arises. A half dozen or more plants can be obtained from one leaf. Some operators cut off the ribs, instead of wounding them with a prick. Many gardeners prefer to divide the leaf into two nearly equal parts, and then set each part, or the better one, upright in the soil, the severed edge being covered. This is shown in Fig. 60. Fewer plants—often only one—are obtained in this manner, but they are strong.

Fig. 58. Clipped Weigela cutting.

When stock is scarce the leaf may be cut into several fan-shaped pieces. The whole leaf may be divided into as many triangular portions as can be obtained with a portion of the petiole, a strong rib, or vein at the base; these inserted and treated like coleus cuttings will all root and make good plants within a reasonable time, say six months. This form of cutting should be two to three inches long by an inch or inch and one-half wide. Ordinarily, in this style of leaf-cutting, the petiole or stalk is cut off close to the leaf and the lower third or fourth of the leaf is then cut off by a nearly straight cut across the leaf. This somewhat triangular base is then cut into as many wedge-shaped pieces as there are ribs in the leaf, each rib forming the center of a cutting. The point of each cutting should contain a portion of the petiole. The points of these triangular portions are inserted in the soil a half inch or so, the cutting standing erect or nearly so. Roots form at the base or point in the ordinary manner.

Leaf cuttings are handled in the same manner as soft stem-cuttings so far as temperature and moisture are concerned. There are comparatively few species in which they form the most available means of multiplication. In some cases, variegation will not be reproduced by the rooted leaf. This is true in the ivy-leaved geranium L’Elegante; a good plant can be obtained, but it reverts to the plain-leaved type.

Fig. 59. Begonia leaf cutting.

Fig. 60. A upright Begonia leaf cutting.

CHAPTER V.

GRAFTAGE.

Graftage.—The process or operation of grafting or budding, or the state or condition of being grafted or budded.

Grafting.—The operation of inserting a bud or a cion in a stock. It is commonly restricted to the operation of inserting cions of two or more buds, in distinction from budding, or the operation of inserting a single bud in the stock; but there are no essential differences between the two operations.

Stock.—In graftage, a plant or part of a plant upon which a cion or bud is set. A free stock is a seedling, in distinction from a grafted stock.

Cion or Scion.—A portion of a plant which is mechanically inserted upon the same or another plant (stock) with the intention that it shall grow.

GENERAL CONSIDERATIONS.—Graftage is rarely employed for the propagation of the species, as seedage and cuttage are more expeditious and cheaper. Its chief use is to perpetuate a variety which does not reproduce itself from seeds and which cannot be economically grown from cuttings.

Nearly all the named varieties of tree fruits and many of those of ornamental trees and shrubs are perpetuated by means of graftage. In some species which present no marked varieties, however, propagation by seeds or cuttings is for various reasons so difficult or uncertain that recourse must be had to graftage. This is particularly true in many of the firs and spruces which do not produce seeds to any extent in cultivation. In other cases graftage is performed for the purpose of producing some radical change in the character or habit of the plants, as in the dwarfing of pears by grafting them upon the quince, the elevation of weeping tops by working them upon upright trunks, and the acceleration of fruit-bearing by setting cions in old plants. It is sometimes employed to aid the healing of wounds or to repair and fill out broken tops. And it has been used to make infertile plants fertile, by grafting in the missing sex in diœcious trees, or a variety with more potent pollen as practiced in some of the native plums. All these uses of graftage fall under three heads: 1. To perpetuate a variety. 2. To increase ease and speed of multiplication. 3. To produce some radical change in nature or habit of cion or stock.

Probably all exogenous plants—those which possess a distinct bark and pith—can be grafted. Plants must be more or less closely related to each other to allow of successful graftage of the one upon the other. What the affinities are in any case can be known only by experiment. As a rule, plants of close botanical relationship, especially those of the same genus, graft upon each other with more or less ease; yet this relationship is by no means a safe guide. A plant will often thrive better upon a species of another genus than upon a congener. The pear, for instance, does better upon many thorns than upon the apple. Sometimes plants of very distinct genera unite readily. Thus among cacti the leafless epiphyllum grows remarkably well upon the leaf-bearing pereskia. It should be borne in mind that union of tissues is not a proof of affinity. Affinity can be measured only by the thrift, healthfulness and longevity of the cion. The bean has been known to make a union with the chrysanthemum, but it almost immediately died. Soft tissues, in particular, often combine in plants which possess no affinity whatever, as we commonly understand the term. Neither does affinity refer to relative sizes or rates of growth of stock and cion, although the term is sometimes used in this sense. It cannot be said that some varieties of pear lack affinity for the quince, and yet the pear cion grows much larger than the stock. In fact, it is just this difference in size and rate of growth which constitutes the value of the quince root for dwarfing the pear. When there is a marked difference in rate of growth between the stock and cion, an enlargement will occur in the course of time, either above or below the union. If this occurs upon the stem, it makes an unsightly tree. If the cion greatly outgrows the stock a weak tree is the result.

Graftage can be performed at almost any time of the year, but the practice must be greatly varied to suit the season and other conditions. The one essential point is to make sure that the cambium layers, lying between the bark and wood, meet as nearly as possible in the cion and stock. This cambium is always present in live parts, forming woody substance from its inner surface and bark from its outer surface. During the season of greatest growth it usually occurs as a soft, mucilaginous and more or less unorganized substance, and in this stage it most readily repairs and unites wounded surfaces. And for this reason the grafting and budding of old trees are usually performed in the spring. Later in the season, the cambium becomes firmer and more differentiated, and union of woody parts is more uncertain. It is also necessary to cover the wounds in order to check evaporation from the tissues. In out-door work wax is commonly used for all species of graftage which wound the wood itself, but in budding, the loosened bark, bound down securely by a bandage, affords sufficient protection. It is commonly supposed that an ordinary cleft-graft cannot live if the bark of the stock immediately adjoining it is seriously wounded, but the bark really serves little purpose beyond protection of the tissues beneath. A cion will grow when the bark is entirely removed from the stub if some adequate protection can be given which will not interfere with the formation of new bark. The cion must always possess at least one good bud. In most cases, only buds which are mature or nearly so are used, but in the grafting of herbs very young buds may be employed. These simple requirements can be satisfied in an almost innumerable variety of ways. The cion or bud may be inserted in the root, crown, trunk or any of the branches; it may be set under the bark simply or inserted into the wood itself in almost any fashion; and the operation may be performed either upon growing or dormant plants at any season. But in practice there are comparatively few methods which are sufficiently simple and expeditious to admit of general use.

Graftage may be divided into three general divisions, between which, however, there are no decisive lines of separation: 1. Bud-grafting or budding, in which a single bud is inserted upon the surface of the wood of the stock. 2. Cion-grafting or grafting proper, in which a detached twig bearing one or more buds is inserted into or upon the stock. 3. Inarching or grafting by approach, in which the cion remains attached to the parent plant until union takes place. Each of these divisions can be almost endlessly varied and sub-divided, but in this discussion only the leading practices can be detailed. The following enumeration, after Baltet, will give a fair idea of the kinds of grafting which have been employed under distinct names:

1. Bud-Grafting or Budding. 1.—Grafting with shield-buds. Bud-grafting under the bark, or by inoculation. ” ” ordinary method. ” ” with a cross-shaped incision. ” ” ” the incision reversed. ” ” by veneering. Bud-grafting, the combined or double method. 2.—Flute-grafting. ” ” common method. ” ” with strips of bark.

2. Cion-Grafting or Grafting Proper. 1.—Side-grafting under the bark. ” ” with a simple branch. ” ” with a heeled branch. ” ” in the alburnum. ” ” with a straight cleft. ” ” with an oblique cleft. 2.—Crown-grafting. Ordinary method. Improved method. 3.—Grafting de precision. Veneering, common method. ” in crown-grafting. ” with strips of bark. Crown-grafting by inlaying. Side-grafting by inlaying. 4.—Cleft-grafting, common single. Cleft-grafting, common double. ” ” oblique. ” ” terminal. ” ” ” woody. ” ” ” herbaceous. 5.—Whip-grafting, simple. ” ” complex. Saddle-grafting. 6.—Mixed-grafting. Grafting with cuttings. When the cion is a cutting. When the stock is a cutting. When both are cuttings. Root-grafting of a plant on its own root. ” ” ” ” the roots of another plant. Grafting with fruit buds.

3. Inarching or Grafting by Approach. 1.—Method by veneering. ” ” inlaying. English method. 2.—Inarching with an eye. ” ” a branch.

Particular Methods.—Budding. Budding is the operation of inserting a single bud, bearing little or no wood, upon the surface of the stock. The bud is nearly always inserted under the bark of the stock, but in flute-budding a piece of bark is entirely removed and the bud is used to cover the wound. There is no general rule to determine what species of plants should be budded and which ones cion grafted. In fact, the same species is often multiplied by both operations. Plants with thin bark and an abundance of sap are likely to do best when grafted; or if they are budded, the buds should be inserted at a season when the sap is least abundant to prevent the “strangulation” or “throwing out” of the bud. In such species the bark is not strong enough to hold the bud firmly until it unites; and solid union does not take place until the flow of sap lessens. Budding is largely employed upon nearly all young fruit-trees, and almost universally so upon the stone-fruits. It is also used in roses, and many ornamental trees. Budding is commonly performed during the growing season, usually in late summer or early fall, because mature buds can be procured at that time and young stocks are then large enough to be worked readily. But budding can be done in early spring, just as soon as the bark loosens; in this case perfectly dormant buds must have been taken in winter. Budding is always best performed when the bark slips or peels easily. It can be done when the bark is tight, but the operation is then tedious and uncertain.

Shield-budding.—There is but one style of budding in general use in this country. This is known as shield-budding, from the shield-like shape of the portion of bark which is removed with the bud. Technically, the entire severed portion, comprising both bark and bud, is called a “bud.” A shield bud is shown natural size in Fig. 61. This is cut from a young twig of the present season’s growth. It is inserted underneath the bark of a young stock or branch, and is then securely tied, as shown in Fig. 65.