Fig. 85. Peony root-graft.
Herbaceous-grafting.—In the preceding pages, the discussions have had to do with cions which are dormant or at least well-hardened, and with stocks which contain more or less hard woody substance. But herbaceous shoots can be grafted with ease. All such plants as geraniums, begonias, coleuses and chrysanthemums can be made to bear two or more varieties upon the same individual. Almost any style of grafting can be employed, but the veneer, cleft and saddle-grafts are preferred. Shoots should be chosen for stocks which are rather firm, or in the condition for making good cuttings. The cions should be in a similar condition, and they may be taken from the tips of branches or made of a section of a branch. The union should be bound snugly with raffia, and the plant set in a propagating frame, where it must be kept close for a few days. It is not necessary, in most cases, to use wax, and upon some tender stocks the wax is injurious. Moss may be bound about the graft, but unless the union is first thoroughly covered by the bandage, roots will start into the moss and the parts will fail to unite. The growing shoots of shrubs and trees can also be grafted, but the operation is rarely employed. In various coniferous trees (as pines and spruces) the young shoots are sometimes cleft or saddle-grafted in May, the parts being well bandaged with waxed muslin or raffia, and shaded with paper bags. The walnut and some other trees which do not work readily are sometimes treated in this manner.
Fig. 86. Bark-grafting.
A little known species of herbaceous-grafting is the joining of parts of fruits. It is easily performed upon all fleshy fruits like tomatoes, apples, squashes and cucumbers. When the fruit is half or more grown, one-half is cut away and a similar half from another fruit is applied. Better results follow if the severed side of the parent or stock fruit is hollowed out a little, so as to let the foreign piece set into the cavity. The edges of the epidermis of the stock are then tied up closely against the cion by means of bass or raffia. The two parts are securely tied together, but no wax is required. This operation succeeds best under glass, where conditions are uniform and winds do not blow the fruits about.
Even leaves may be used as stocks or cions. Any such succulent and permanent leaves as those of the house-leeks, crassula, and the like may have young shoots worked upon them, and leaves which are used as cuttings can often be made to grow on other plants.
Seed-grafting.—A novel kind of grafting has been described in France by Pieron, which consists in using a seed as a cion. This has been used upon the grape. A seed is dropped into a gimlet-hole made near the base of the vine while the sap is flowing in the spring. The seed germinates, and after a time the plantlet unites with the stock.