This dainty plant may be roughly divided into three classes — the compact or dwarf kind, the free-growing, spreading kind and the tall perennials. It is the dwarf type which is chiefly used for bedding out, being sown in winter under glass and transplanted into boxes until sufficiently established for bedding-out. The spreading varieties are raised for filling hanging baskets and providing edgings for window boxes.
Various shades of blue as well as white may be had in both these kinds. Fine examples of the tall perennials are Lobelia syphilitica (blue) to about 2 ft. and cardinalis and fulgens varieties, mostly brilliant scarlets to about 3 ft. They are susceptible to late spring frosts and unless protected must not be planted till early June. Most varieties are only fairly hardy and need some protection during the winter. Therefore lift them after flowering and store in a frame or cooltill spring. The violet-wine variety Jean is hardier than most. Lobelias need a rich, free soil and plenty of water during the summer. Increase by division in spring.