Lobelia is a half-hardy annual with more than 360 species, including varieties such as asthma weed, Indian tobacco and vomitweed. Bushier varieties can be used as edging in flower beds, and the trailers variety are good for hanging baskets and container gardens. Though many lobelia varieties are found in temperate climates, the plant is frost-hardy to 32 degrees F. This flowering herb is used to treat asthma and stomach ailments.
Sow Seeds Indoors
Plant the tiny seeds of lobelia indoors in a 3-inch pot of multipurpose compost from January through March. Sow the seeds evenly over the compost, but don't cover. Keep the seeds moist, and place the pot in a well-lit area. When seedlings sprout, separate them into clumps of four to six, and then transplant each clump to a separate seeding pot.
Harden Off Seedlings Before Planting Oudoors
Place seedling pots outdoors in May for a little bit every day to harden off the lobelia plants. Plant outdoors after the threat of frost is gone.
Plant in Full Sun
Lobelia flowers do best if grown in full sun. Enrich soil in garden beds before planting lobelia with rotted compost or manure. Lobelia needs good drainage, but you need to keep the soil moist.
Lobelia needs nutrients to produce its colorful blooms. Feed every two weeks with a high-potash liquid feed.
Clip Off Spent Flowers
Use shears to cut off dead blooms. This encourages the lobelia to produce more flowers.