Lobelia erinus Seeds | Edging Lobelia
LATIN NAME: Lobelia erinus
COMMON NAME: Edging Lobelia
Plant Profile
Edging lobelia is a South African annual that has been trained into one of the most useful small plants in the garden. It makes a low, dense mound of fine, toothed leaves and covers itself from early summer until frost with two-lipped flowers in a blue that is genuinely hard to find elsewhere, most with a white eye and a yellow blotch at the throat. It trails, it mounds, it seeds about gently, and it asks for nothing more than moisture and a little shade from the worst heat. In a pot or at a path edge it knits the planting together within a month. The species comes in trailing and compact forms, and the trailing ones are the better choice for baskets, while the compact ones suit edging and pots.
Science & Biotechnology
Lobelia erinus belongs to Campanulaceae and is a tetraploid, which is one of the reasons its cultivars are so variable and so easily fixed by selection. The genus is chemically famous for lobeline, a piperidine alkaloid that acts on nicotinic receptors and gave Lobelia inflata its career as an emetic and a smoking-cessation herb; the garden species contains far less but is not a salad. Flower colour is controlled by a small number of anthocyanin and carotenoid steps, and the white-eyed forms are the ancestral type, with the deep blues and the bronze-leaved sorts derived by breeding. Breeding has produced a range of colours from white through lilac to deep blue, and the bronze-leaved forms are grown as much for the foliage as the flower.
Uses & Benefits
It is an edging and basket plant above all, filling the front of a border, spilling over a wall, and knitting the surface of a mixed container together while taller things get going. The blue combines well with yellow and silver, and the trailing forms tolerate more shade than most summer bedding. The flowers are visited by small bees and hoverflies. It is not a medicinal plant in any safe sense, and the ornamental lobelias should be kept out of the kitchen entirely, since the alkaloid load is unpredictable. In a hanging basket it will trail half a metre by August.
Growing from Seed
The seed is dust-fine, so sow it on the surface of a fine, moist compost, press it down and do not cover it, because light is needed for germination. Keep at eighteen to twenty degrees and expect seedlings in two to three weeks. Prick them out in small clumps rather than singly, grow on cool and bright to keep them stocky, and plant out after the last frost. Pinch once for a denser mound, water in dry spells, and shear back lightly in midsummer to provoke a second flush before the frost. Water in the morning so the foliage dries before night. Do not let the seedlings dry out for even a day at the pricking-out stage.
Our Take
The best blue in the summer garden for the space it takes up, and it comes from a packet of dust and a little patience. Sow thinly, keep it cool, and it will do the rest.
Related Reading
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