Cuttings may be taken from various parts of the plant, sometimes even from parts of the leaf, as in the begonia (Fig. 46). More often, however, they are drawn from parts of the stem (Figs. 43-45). As to the age of the twig from which the cutting is to be taken, Professor Bailey says: "For most plants the proper age or maturity of wood for the making of cuttings may be determined by giving the twig a quick bend; if it snaps and hangs by the bark, it is in proper condition. If it bends without breaking, it is too young and soft or too old. If it splinters, it is too old and woody." Some plants, as the geranium (Fig. 42), succeed best if the cuttings from which they are grown are taken from soft, young parts of the plant; others, for example, the grape or rose, do better when the cutting is made from more mature wood. [Illustration: FIG. 43 GRAPE CUTTING Showing depth to which cutting should be planted] [Illustration: FIG. 44. CARNATION CUTTING] Cuttings may vary in size and may include one or more buds. After a hardy, vigorous cutting is made, insert it about one half or one third of its length in soil. A soil free from organic matter is much the best, since in such soil the cuttings are much less liable to disease. A fine, clean sand is commonly used by professional gardeners. When cuttings have rooted well--this may require a month or more--they may be transplanted to larger pots. Sometimes, instead of cutting off a piece and rooting it, portions of branches are made to root before they are separated from the parent plant. This method is often followed, and is known as _layering_. It is a simple process. Just bend the tip of a bough down and bury it in the earth (see Fig. 47). The black raspberry forms layers naturally, but gardeners often aid it by burying the over-hanging tips in the earth, so that more tips may easily take root. Strawberries develop runners that root themselves in a similar fashion. Grafts and buds are really cuttings which, instead of being buried in sand to produce roots of their own, are set on the roots of other plants. [Illustration: FIG. 45. ROSE CUTTING] Grafting and budding are practiced when these methods are more convenient than cuttings or when the gardener thinks there is danger of failure to get plants to take root as cuttings. Neither grafting nor budding is, however, necessary for the raspberry or the grape, for these propagate most readily from cuttings. It is often the case that a budded or grafted plant is more fruitful than a plant on its own roots. In cases of this kind, of course, grafts or buds are used. The white, or Irish, potato is usually propagated from pieces of the potato itself. Each piece used for planting bears one eye or more. The potato itself is really an underground stem and the eyes are buds. This method of propagation is therefore really a peculiar kind of cutting.