PROPAGATION BY LAYERS. 



353 



alburnum to the leaves and buds, and de- 

 scending in an elaborated form by the inner 

 bark, forming in its downward progress a new 

 layer of alburnum, shows sufficiently that even 

 ringing does not interrupt the rising of the sap 

 in spring, so long as the alburnum is not cut 

 through ; yet its descent is interrupted in con- 

 sequence of the incision made during the ope- 

 ration of ringing, and which, although it merely 

 cuts into the alburnum, in no way affects the 

 inner bark. A granulous callosity is formed at 

 the point of interruption, from which roots will 

 in due time protrude. In the case of some 

 trees, if the incision in the layer does not extend 

 half-way through, no granulous matter will be 

 formed the first year ; but, on the other hand, 

 if the incision is made much deeper than half the 

 thickness of the layer, then the ascent of the sap 

 is interrupted, and the shoot naturally dies. 



The manipulations of this mode of propaga- 

 tion are exceedingly simple ; the following will 

 explain the routine. In ordinary cases of nur- 

 sery layering, the plant to be propagated is called 

 the stool, and hence all nurserymen have their 

 stool ground, in which is planted every kind of 

 tree or shrub to be thus increased. Stools are 

 cultivated only for the production of shoots 

 proper for layering, hence they are cut close 

 down to facilitate the operation. The stool 

 occupies the centre, the young healthy wood is 

 reserved, and the slender and unhealthy is cut 

 out. The ground around being loosened up, 

 shoot after shoot is gently drawn down from 

 the stool ; a notch, tongue, or other incision is 

 made on its under side, and from 6 to 10 inches 

 from its base the earth 

 is opened, and the layer is 

 fitted into the soil, of a 

 depth according to its na- 

 ture and strength. It is 

 then secured in the desired 

 position by a hooked peg, 

 fig. 127, a single, 6 double, 

 or by a shoot of flexible na- 

 ture, such aswillow, which is 

 twisted at the middle, and 

 the two ends thrust into 

 the ground, one on each side 

 of the layer ; the soil is laid 

 over it, the point of the shoot 

 cut off, leaving one or two 

 eyes above the ground sur- 

 face. The incision for the 

 most part consists in simply entering the knife 

 below a bud, and cutting to such a depth as has 

 already been noticed, and drawing the knife up- 

 wards, leaving what is in common phraseology 

 called a tongue ; sometimes a simple notch is cut 

 out : in the former case, a bit of tile, thin stone, 

 or chip of wood, is inserted to keep the tongue 

 open or the wound from collapsing. Some plants 

 will root freely without any incision being 

 made, others if only a small portion of the bark 

 be pared off ; some if they are slightly twisted or 

 fractured, while others will not, unless a ring of 

 bark be taken off or tightly bound round with a 

 piece of wire. The effects of all these are the 

 same — namely, the obstruction offered to the 

 descending sap, and the consequent formation 



Fig. 127. 



PEGS FOR LAYERING. 



of granulous matter, and the after protrusion of 

 roots. In the case of trees which are too 

 strong or too brittle to bend down, so that 

 their side branches may be laid in the ground, 

 the process of plashing them — or of elevating 

 the soil in pots, boxes, or raised banks — must be 

 had recourse to. In the former case the branch 

 may be plashed — that is, cut in its under side — 

 causing the direction of the fracture to run to- 

 wards the main stem, cutting and proceeding 

 until the branch will readily bend as low as re- 

 quired, taking care, however, that a sufficient 

 portion of the bark remains unbroken on the 

 upper side. The side branches may then be 

 laid in the usual manner. 



The time required for layers becoming suf- 

 ficiently rooted to be fit for separation from 

 the stool, depends on a variety of circumstances. 

 Some trees and a few shrubs require two years ; 

 roses, and the majority of similar shrubs, if 

 their present year's wood be operated upon 

 when about half ripened, will be fit for removal 

 the same autumn ; if laid in spring or the winter 

 preceding, they will be ready about the same 

 time; while herbaceous and soft-wooded plants 

 will produce their roots in a few days or weeks : 

 and the same will occur in the case of many 

 plants under artificial excitement. 



Layering herbaceous plants is had recourse to 

 in the case of rare or valuable plants, as being 

 attended with much less risk of losing the 

 plant than if the more ordinary process of mak- 

 ing cuttings were adopted : it is also had re- 

 course to with a view of getting stronger plants 

 in a less space of time. The process is com- 

 menced when the shoots are of sufficient lengths 

 and have attained some degree of consistency, 

 which state usually occurs about the time the 

 plant is coming into 

 flower. The annexed 



<"ig. 128. 



cut, fig. 128, shows 

 the principle in the 

 case of a double sweet- 

 william, dianthus bar- 

 batus, no. pleno. The 

 lower leaves of the best- 

 formed shoots being 

 cut off, a thin budding- 

 knife is inserted below 

 a joint or bud, and is 

 passed half through 

 the branch, and con- 

 tinued about three- 

 quarters of an inch 

 upwards, the bending 

 of which upwards 

 keeps the cut open, 

 while the shoot is 

 pegged down, and 

 covered with soil, somewhat sandier than 

 that in which the plants are growing. The 

 form of the peg used in laying is as represented 

 in fig. 127 a, b; but often, and perhaps more 

 conveniently, a small twig of willow may be 

 used, cut to the length of 6 or 8 inches, and 

 bent over, both ends of which are thrust into the 

 ground, and keep the layer in its proper place. 

 And in some extreme cases, where a shoot is 

 sent from a distance, or accidentally separated 



