LAYERS. so 
lows: The bundles of cuttings are heeled in as recommended. 
In the spring they are taken out, and buried close together, with 
the butt ends uppermost, in a warm sunny spot, and covered 
with about six inches of soil. A hotbed frame, with sash, is then 
put over the spot, to warm the soil. Sometimes, instead of 
using sash, the soil over the cut- 
tings is covered with a foot or 
more of fermenting manure. In 
either case the soil is warmed, 
and the formation of roots 
encouraged. In using the solar 
Figure 13. The solar pit, 3 z 
showing bundles of cuttings pit the rooting process should 
in place under glass. not be carried so far as to permit 
roots to show plainly, as they are liable to be broken off in 
planting out; but the cuttings should be planted out as soon as 
they show signs of healing over on the butt end. This healing- 
over process is called callousing, and in many plants neces- 
sarily precedes the formation of roots. 
LAYERS. 
Layers are portions of the branches of trees, shrubs or vines 
which are covered with earth without being separated from the 
parent plant and there take root and grow. These are cut off 
from the main plant in autumn or spring, and form new plants. 
Almost all trees and other plants can be rooted in this way, but, 
while some root very easily, others require so long a time to do 
so as to make it impracticable with them. 
The growing of trees from layers is seldom practiced in this 
country, but in some European nurseries it is a common means 
by which to increase special varieties of trees. For this purpose 
what is commonly known as mound layering is often used. 
This consists simply of drawing the soil up around the sprouts 
that come from the stump of a tree, covering the base of them 
about a foot in depth. It may be done at any time of the year 
after the sprouts are two or more feet high, but preferably in the 
spring. After the sprouts have become well rooted they may be 
removed in spring or autumn and treated the same as seedlings. 
Layering is sometimes practiced in European forests to fill up 
vacancies, and a similar method is often employed in nurseries. 
