Height 10-23cm (4-9in)

Planting distance 10cm (4in)

Flowers late spring to autumn

Fertile moisture retentive soil

Sunny or partially shaded site

Half-hardy perennial grown as an annual

Though grown as an annual, Lobelia erinus is correctly a half-hardy perennial. It is a small plant, only 10-23cm (4-9in) high, with light green leaves, and it produces a mass of small blue flowers from late spring until autumn frost.

More popular than the species are the many varieties which may be either compact, making neat 10-15cm (4-6in) high domes, or trailing in a spread of 30cm (1ft) across. The colour range of the varieties embraces white, pale blue, deep purplish-blue and wine-red.

The varieties with a compact habit are normally used to edge beds while those with a trailing habit look effective in hanging baskets, window-boxes and other containers.

Popular varieties

The following varieties are readily available.

‘Blue Moon’ is a compact, early-flowering variety. The large flowers are clear blue.

‘Cambridge Blue’ is neat and compact with light blue flowers.

‘Cascade Mixed’ is a mixture of cascading varieties coming in blue, mauve, red and white, usually with white eyes.

‘Crystal Palace’ is a compact variety bearing rich deep blue flowers. The foliage is bronze-coloured.

Lilac Fountain’ is a trailing variety, with pale lilac-pink flowers. Other strains in this series include white and blue-coloured varieties.

‘Mrs Clibran’ is a compact plant bearing rich violet-blue flowers with white eyes.

‘Red Cascade’ is a trailing variety with wine-red, white-eyed flowers.

‘Rosamund’ is a compact variety bearing crimson flowers with white eyes.

‘Sapphire’ is a trailing variety with white-eyed, glossy deep blue flowers.

‘Snowball’ is a compact variety with white flowers, though some are slightly tinged with blue.


Sow the seeds in late winter in pans of seed compost and keep at a temperature of 16-18°C (61-64°F). Prick out the seedlings in groups of three or four — they’re too small to prick out individually – and grow on at a temperature of 13-16°C (55-61°F). Harden off and plant out in late spring.

Plant lobelia in rich moist soil in a sheltered, sunny or partially shady position.

Pests and diseases

Damping off and root rot can cause the plants to wilt and stem rot may show as pale spots on the leaves of seedlings.

22. February 2012 by Dave Pinkney
Categories: Annuals, Biennials, Bulbous Plants, Featured Articles | Tags: , , , | Comments Off on Lobelia


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