56 THE NURSERY-BOOK. 



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 ad- 

 visable method of 

 treatment varies with 



the season and locality 

 Fig. 5- Single-eye Grape cutting. . 



as well as with the 



species or variety. It is well known, for instance, that the Dela- 

 ware 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. 



Many coniferous plants are increased by cuttings on a large 

 scale, especially retinosporas, arbor-vitaes, 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 ex- 

 plicit directions, see Thuya and Retinospora in Chapter VI.) 



Most remarkable instances of propagation by means of por- 

 tions 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 propa- 

 gation. 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 



