PROPAGATION BY LAYERS. 



273 



branches of trees and shrubs that rest on the soil, and by their shade keep it 

 moist, which, after some time, root into it. Whatever mode of interrupting 

 the sap be adopted, the wounded part of the layer from which roots are 

 expected to proceed must be covered with soil, moss, or some other suitable" 

 material kept moist, or it must be partially or wholly immersed in water. 

 Layering, from the certainty which attends it, was formerly much more 

 extensively employed as a mode of propagation than it is at present ; the 

 art of rooting cuttings being now much better understood, and being chiefly 

 adopted in house and in herbaceous plants ; and layering being confined in 

 a great measure to hardy trees and shrubs, of which it is desired to produce 

 plants that will speedily produce flowers, or that cannot otherwise be so 

 readily propagated. 



621. The state of the plant most favourable for layering is the same as that 

 most suitable for propagation by cuttings (574 to 576). The wood and 

 bark should be soft and not over ripe, and this is most likely to be the case 

 with lateral shoots produced near the surface of the soil, or in a moist atmo- 

 sphere. The worst shoots are such as are stunted and hide-bound, though 

 there are no shoots whatever, unless such as are in a state of disease, that 

 will not root by layers, if sufficient time be allowed them. Layers, like 

 cuttings, may be made either of ripe wood in the autumn or spring, or of 

 growing wood any time in the course of the summer; the only condition, in 

 the latter case, being that the part of the shoot where the sap is interrupted 

 be somewhat mature, or firm in texture. 



622. Hardy trees and shrubs, with reference to layering, may be divided 



into two kinds, those which, when cut 

 down, throw up shoots from the collar, that 

 is, technically, which stole, such as most 

 kinds of deciduous trees and shrubs ; and 

 those which do not stole, such as all the 

 conifers. The former are planted and cut 

 down, and layers made of the young shoots 

 which proceed from the collar ; while the 

 A latter are either laid entirely down, and 

 J| lL their branches extended along the surface 

 of the soil, and the extremities of all the 

 shoots layered, or such side branches as 

 can be bent down to the soil are made fast 

 there by hooked pegs, and their shoots 

 layered. When the shoots to be layered 

 are small, they are frequently twisted or 



Fig. 183. Layering with the tongue made in slit through at the point where the roots 



the undenide of the shoot. are to j, e pro duced ; but when they are 



strong the knife is entered beneath a joint, and the shoot cut half through, 

 and the knife afterwards turned up half an inch or more, so as to form what 

 is technically called a tongue (fig. 183, a), and the shoot being bent down 

 and its point turned up, the wound is kept open as at b ; the shoot being kept 

 down by a hooked peg, or by a portion of a twig, first twisted to render it 

 tough, and next doubled, as at c, one or more buds being left on the layer, r/, 

 the wound being kept open by the bent position of the shoot. When the 

 shoots are small or brittle, in order to lessen the risk of breaking them by 

 tonguing below, the incision is made above, and the tongue kept from uniting 



