260 THE FLOWER-GARDEN, [chap. viii. 
every time the old flowers are removed, in 
order to prepare it for the new ones. 
Biennials are plants which do not flower 
till the second year. They are generally 
sown in March, April, or May, and are 
transplanted in September, to the situations 
where they are to flower the following year. 
The best known of these flowers are the 
different kinds of hollyhock, snapdragon, 
Canterbury bells, wallflowers, sweet-williams, 
(Enotheras, and Brompton stocks; but there 
are many others extremely beautiful and 
equally well deserving of cultivation. Most 
of the biennials may be propagated by layers 
or cuttings, and thus treated, they will last 
four or five years. 
Perennial herbaceous plants are so nume¬ 
rous, that few general directions can be 
given for their culture, and it will be neces¬ 
sary to treat of the principal families sepa¬ 
rately. Perennial flowers are generally pro¬ 
pagated by layers, cuttings, offsets, suckers, 
and division of the root; for when raised 
from seed, many of the kinds do not blossom 
for several years. When propagated by 
layers, the earth which is pressed over the 
