Lobelia is a genus of flowering plants in the family Campanulaceae, comprising 360 - 400 species. It is native to the tropical to warm temperate regions of the world. It is commonly known as Lobelia, Asthma Weed, Indian Tobacco, Pukeweed, and Vomitwort. The genus is named after Matthias de Lobel (1538 - 1616), a Belgian botanist.
There are about eleven species native to Mexico and Central America have spurs on the flowers. Some species are cultivated as ornamental plants in gardens, including Lobelia cardinalis (Cardinal Flower or Indian Pink), Lobelia siphilitica (Blue Lobelia), Lobelia fulgens and Lobelia erinus (Edging Lobelia).
Lobelia erinus (Edging Lobelia, Garden Lobelia or Hanging Lobelia) is native to southern Africa, from Malawi and Namibia south to South Africa. It is perennial in subtropical climates and is often grown as annual in colder area. Lobelia erinus is a very popular ornamental plant in gardens. It can be grown in beds, large pots, window boxes, and in hanging baskets. It has long flowering period, from mid spring to early autumn. Many cultivars have been selected for garden use, with a wide variety of colors, inclusing white, pink, red, pale to dark blue, and purple. The better known cultivars are 'Blue Moon', 'Cascade', 'Gracilis' and 'Rosamund'.
Lobelia inflata (Indian Tobacco) is native to eastern North America, from southeastern Canada south through to the eastern United States to Alabama and west to Kansas. Lobelia inflata is an annual or biennialherbaceous flowering plant growing to 15 - 100 cm tall. It has stems that are covered with tiny hairs, and its leaves are about 8 cm long, ovate and toothed. From midsummer to autumn, it bears flowers that are violet in color with tinted yellow on the inside, . Lobelia inflata is used by herbalists for treatment of asthma, hence its nickname Asthma Weed.
Lobelia pratioides (Poison Lobelia) is a plant native to Australia. It has leaves that are 6 - 15 mm long. Flowers of pale blue or lilac color are borne from November to January. The rounded fruit is about 5 mm. It grows in damp areas within grasslands and grassy woodland in South Australia, Tasmania and Victoria.
Lobelia cardinalis (Cardinal Flower) is native to the Americas, from southeastern Canada south through the eastern and southwestern United States, Mexico ans Central America to northern Columbia. It is a perennial herbaceous plant found growing in wet places, streambanks, and swamps. It can grows up to 1.2 m tall, has leaves that are broad, lanceolate to oval with a toothed margin, 20 x 5 cm long and broad. It produces vibrant red, deeply five-lobed flowers in an erect raceme of up to 70 cm tall in summer to autumn. It also comes in other forms such as 'Alba' which has white flowers and 'Rosea' in pink. Lobelia cardinalis is pollinated by hummingbirds.
Lobelia tupa, 1.8 x 1 m, is a useful perennial in mixed border. It has grey-green leaves and tall racemes of bright reddish-orange flowers.
Lobelia grows well in full sun or partial shade, in fertile and moisture-retentive soil. Propagation is by seed or division in spring. Slugs and snails are pests that affect the plant.