The flowers are blue to violet in wild plants, with a five-lobed corolla 8–20 mm across; they are produced in loose panicles.

Lobelia erinus is a very popular edging plant in gardens, especially for hanging baskets and window boxes.

In temperate zones it is grown as a half-hardy annual, i.e. sown under glass with some heat in spring, then planted out when all danger of frost has passed.

[6] Numerous cultivars have been selected, either with a bushy or a trailing habit, in a wide range of flower colours, including white, pink, magenta ("red"), pale to dark blue, and purple, often with a prominent white eye.

[4] In the United Kingdom the following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:[8] Media related to Lobelia erinus at Wikimedia Commons