Quick Guide: summer, hardy, sun/semi-shade, height: 30cm - 1.2m/1-4ft, width: 30cm/12in
There are two types of annual delphiniums, namely D. ajacis, known as rocket larkspur, and D. consolida, the common larkspur. Both are typical cottage garden plants, their tall spikes clothed with flowers of blue, white, pink or purple. They bring height and grace to the summer border, and are suitable as cut flowers.
PROPAGATION Sow seed directly in the growing site in successive sowings throughout the spring. Thin the seedlings to about 30cm/12in depending on variety. Alternatively sow seed in the autumn and protect with cloches over winter.
GROWING Delphiniums need well-cultivated, fertile soil and a site sheltered from wind. Provide twiggy sticks for support for taller varieties.
VARIETIES D. ajacis, Hyacinth-flowered types: thickly set, double flowers, on blunt stems up to 60cm/24in high; D. consolida, Giant imperials: up to 1.2m/4ft, branching out from the base; Stock-flowered types: up to 90cm/3ft, best for cutting.
POSSIBLE PROBLEMS Slugs and snails damage young shoots. Crown, root and stem rot cause plants to collapse. Cucumber mosaic virus shows as mottled leaves.
