chap, i.] STIRRING TIIE SOIL. 23 
bushy stems, and very weak and slender roots 
like the pea. Ligneous plants should never 
be earthed up, to avoid injuring the vital 
knot, which forms the point of separation 
between the main root and the stem, and 
which gardeners call the collar, crown, neck 
or collet. This part in trees and shrubs 
should never be buried, as if it be injured 
by moisture so as to cause it to rot; or if it 
be wounded in any way, the plant will die. 
A deciduous tree may be cut down close 
above the collar, and it will throw up fresh 
shoots, or the roots may all be cut off close 
below the collar, and if that part be unin¬ 
jured fresh roots will form ; but if a tree 
be cut through at this vital part it never 
can recover. 
A trowel is another instrument used 
in stirring the soil, but of course it can 
only be employed in boxes of earth in bal¬ 
conies, &c. 
Raking is useful in smoothing the soil after 
digging, and in collecting weeds, stones, &c., 
and dragging them to one side, where they 
may be easily removed. An iron-toothed 
rake is generally used for the ground, and a 
