Family: Campanulaceae

There are over 300 species of annuals and herbaceous perennials in this genus, found in most tropical and temperate regions of the world. Their range of habitats is most diverse, from marshes to woodlands, mountain slopes to near deserts. The leaf shape and flower for­mation are variable, but the leaves are generally dark green. The flowers can he brilliant blue, red, yellow or white. Because of the intensity of colour, they look their best in massed plantings or in borders and rockeries. A number of species have medicinal uses.

Species

L. cardinalis, cardinal flower, zone 3, is native to North America. This herbaceous perennial grows to 1 m (3 ft) high, with bright red flowers in summer to early autumn. It thrives in moist ground.

L. erinus, edging lobelia, zone 10, is a small annual, to 15 cm (6 in), used for edging garden beds and also for pots and hang­ing baskets. Many cultivars are available includ­ing 'Cambridge Blue' and 'Crystal Palace' with blue flowers on compact plants. Good trailing cultivars, ideal for hanging baskets, are 'Blue Cascade', 'Hamburgia' and 'Sapphire'.

L. inflata, Indian tobacco, zone 3, is a hairy annual, cultivated for the alkaloids in the leaves which help chest ailments.

L. laxiflora, zone 9, is a shrubby grower, very easily grown, to 1 m (3 ft), with tubular, red flowers with yellow lobes.

L. siphilitica, blue cardinal flower, zone 5, is a perennial, to 1 m (3 ft), with crowded sprays of summer, blue flowers.

L. x speciosa, zone 3, covers a group of hybrid perennials, all growing to about 1 m (3 ft). Named cultivars with bright pink or red flowers are popular for perennial borders.

Cultivation

Most of the annuals are frost-sensi­tive, while the perennials are quite hardy and thrive in cooler regions. All prefer a rich, moist soil. Most species prefer a sunny situation, but some do well in partial shade. An application of liquid fertilizer prior to flowering will increase the intensity of the flower colour. Propagate annuals from seed sown in spring under glass and plant out when frosts are over. Perennials can be lifted and divided in late winter or spring.

Climate

There are species suited to various climatic zones.