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. [Illustration: 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. [Illustration: 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.)