Dainty herbaceous perennial, native to South Africa, flowering from spring to autumn with small blue to violet, pale-centered flowers in loose panicles, fine stems and tiny leaves. Flowers are 1-2 cm across, and have five-lobed corollas with three larger and two smaller lobes. Lower leaves are oval in shape, 1-3 cm long, often flushed with a reddish-purple tinge, and have toothed margins. Leaves on flowering stems are linear, and usually have an entire margin. Many cultivars are available, with a trailing or upright habit, and flower colours ranging from shades of purple and blue, to pink, cerise, and white. Pictured here is Lobelia erinus 'Lucia Dark Blue', a trailing variety with gorgeous sky-blue flowers.
Prefers a sunny position (partially shaded in areas with hot summers) in well-draining soil. Looks best when the weather is cool, but usually stops flowering during summer when temperatures become too high. If that happens to your plants, you can cut them back to encourage another flush of flowers later in the season. Lobelia erinus 'Lucia Dark Blue' is more heat tolerant than many other varieties. For best performance, apply compost and fertiliser once a year. Fertilise container plants once a month. Suitable for coastal areas. Tolerates light frosts, and in colder climates Lobelia erinus is generally grown as an annual.
Trailing varieties are particularly attractive when allowed to spill over the edges of containers, window boxes and hanging baskets. Upright varieties make great edging plants and colourful additions to rock gardens.