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Grafting and budding are means of propagation not previously described. They are propagative methods for most fruit tree varieties and for ornamental woody plants that do not come true from seed and the cuttings of which do not take root easily. A grafted tree consists of two parts, scion and stock. The scion is cut from a twig of the variety sought to develop, and it is from the scion that the stem of the plant is to be developed. The stock is the part from which the root system is to be developed. It is usually of the same or a closely related variety. A cross cut through the trunk of a tree would reveal various layers, one of which, the cambium, is the thin layer of cells between the wood and bark from which new tissues grow. The union of stock and scion must bring the cambium of each together until the two parts have united in growth. In budding, a single bud is used instead of a scion, and it is done during the growing season, whereas grafting usually is undertaken with dormant scions, in the spring or winter. An ideal stock would be adaptable to climate
conditions in which it will grow, as hardy as the variety grafted onto
it, insect and disease resistant, reasonable in cost, and capable of easy
propagation. The names of grafts usually indicate the
position on the stock at which the union is effected. Root grafts are
made on mature root tissue, stem grafts high on the stem, crown grafts
on the stem near the ground, and top grafts on the branches. They are
further classified according to the technique used in making the union,
such as whip graft, cleft graft, splice graft, veneer graft, and bark
graft. Cut the upper end of the stock the same
way and fit them together, making sure that the cambium layers of the
two are together on one side at least. They then are tied together with
light twine dipped in melted grafting wax, drained, and cooled. Tie the
two pieces together firmly but not so tightly that the twine cuts the
bark. When the winding has been completed the twine may be broken off
and will stay in place without being tied. Do not use twine so durable
that it will not decay in time to avoid constriction of the graft after
growth starts. A light tape bandage may be used instead of twine. As soon as the ground can be worked, in early spring, the graft should be planted, while still dormant, putting the whole union and all of the scion except the top bud under ground. Plant in rich, well-drained soil, packing it firmly around the roots. Keep the planting clear of weeds and when lateral shoots develop pinch them out, without disturbing the main stem leaves, to throw all growth into the terminal bud until the main stem attains a height of about 30 inches.
When the stock is larger than the scion
the cleft graft frequently is used, carrying out the operation usually
while both are still dormant, in late winter or early spring. Grafts of evergreens and some deciduous trees for landscape usually do not succeed outdoors because of slow union. Most evergreen grafting must be done in specially equipped greenhouses and is not an undertaking for unskilled gardeners. One of the most frequently used evergreen grafts is the veneer graft, with the junction made in the stem of the stock just above the surface of the soil in which the plant stands. A narrow wedge is sliced down the stem about an inch long. The lower end of the scion is trimmed to fit this slot. After the scion is inserted, the union is bound with twine dipped in grafting wax, but no other wax is poured over the juncture. The grafted plant must be kept free of fluctuating temperatures, and a night temperature of about 6o degrees should be maintained. Budding is an inexpensive propagative method for various deciduous plants, with only one bud being used for the scion instead of 3 or more as is usually the case of the grafted scion. Buds are taken from wood of the current season which has grown to the point at which the middle portion of the bud stick is fully developed. Buds should be cut at the time they are to be used. The best time for this method of propagation is the latter part of the summer, after the buds have matured sufficiently and the stocks have achieved active growth to facilitate peeling of the bark. Shield budding is the most popular form of this propagative method. A shield consisting of a portion of the bark and a thin layer of wood carrying the bud is sliced from the twig. A T-shaped incision is made in the bark of the stock, bark peeled back slightly along the edges of the cut, and the shield is slipped beneath the lips of the cut bark. Gauze dipped into melted paraffin may be wrapped around the union to tape it in place. Shade is helpful in such an undertaking and it is wise to make the incision on the north side of the stock, away from the prevailing direction of the sun.
Correct use of essential fertilizersIn applying fertilizer to plantings of shrubs and trees, the gardener must guard against overstimulation and untimely stimulation. His goal in fertilization is the promotion of a steady growth throughout an extended season. By fertilizing too late in the fall he makes for growth that does not mature before the onset of freezing weather; unripened wood is particularly susceptible to injuries from cold, and even matured wood may be killed by a freeze if growth is in progress. Overstimulating may produce a vigorous soft growth, more susceptible to some diseases than ordinary growth.
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