252 THE NURSERY-MANUAL 



Many of the short-lived perennials bloom most strongly the 

 second year from seed, and they are treated as biennials by gar- 

 deners. Examples are foxglove, sweet William, hollyhock, and 

 some of the larkspurs and campanulas. Others are treated both 

 as annuals and biennials, as snapdragon and pansy, although 

 perhaps really perennial. 



Most of the plants known in gardens as biennials may be grown 

 from seeds sown in summer, preferably in flats in a frame. In 

 autumn the young plants may be transferred to their blooming 

 quarters, or they may be transplanted to other flats or to pots 

 and carried over winter in a frame. If started in spring, many 

 of the kinds become too large by autumn to handle well, and 

 they may even begin to bloom and weaken themselves for next 

 year's use. Fresh strong well-leaved rosettes or clumps are 

 needed in spring to produce the best bloom for the year. Some 

 of the strongest plants of the perennial-biennials may be carried 

 over for a second season of bloom, as the hollyhock, but the best 

 results are not usually to be had by this practice, specially of the 

 highly bred types. 



Particular strains may be propagated asexually, by cuttings and 

 sometimes by division and offsets. The cuttings are treated in 

 practically the same way as seedlings. 



If one has a greenhouse or well-heated hotbed, some of the 

 biennials may be made to bloom the first year by starting the 

 seeds in winter or early spring and carrying them forward briskly. 

 In this case, the plants are practically annual, and usually are 

 not bloomed the second season. 



Bifrenaria. Orchidacece. 



Propagated by offsets and division. See Orchids, page 372. 



Bignonia. Bignoniacece. 



The plants known to cultivators as bignonia are now distributed 

 in several genera. Increase is by seeds, when obtainable. Stout 

 short-jointed side growths make good cuttings of the greenhouse 

 species, taken in spring and kept in a warm propagating-box. 

 Rooting takes place in six to ten weeks if they are carefully 

 watered and handled. 



Billbergia. Bromeliaceae. 



As seeds are rarely obtainable under cultivation, the plants are 



