Lobelia is prized for window boxes, hanging baskets, planters, and ground covers. Although the plants do best in full sun and moist, rich soil where summers are cool, they will grow surprisingly well in hot areas if given partial shade.
Lobelia is not sown directly in the garden because it does not begin to flower until two months after seed is planted. Start the seeds indoors 10 to 12 weeks before the last frost is due; since the seeds are very small, plant them on top of finely prepared soil without covering them. Most nurseries and garden supply stores offer started plants already in bloom. Transplant after all danger of frost is past, spacing them 4 to 6 inches apart. Remove flower spikes after blooming to produce further growth. ‘Rosamund’ is the pictured cultivar.