Diascia: The Annual and Perennial Species Summer Flower
Diascias grow naturally in South Africa: the annual species in the low-lying, dry regions, and the perennials in the mountains, particularly the Drakensbergen, where they flower on rocky ledges or along the banks of brooks. The perennial species from the mountains are the types cultivated in our part of the world. They rarely survive northern winters, however, and stem cuttings are therefore taken in late summer, and root cuttings in autumn (these are kept frost-free). Alternatively, they are propagated by seed in early spring. If sown early, nearly all species and all culti-vars will flower by mid-summer of the same year. The only seed on sale is that of Diascia barberae.
Sow indoors in February-March. The seeds will germinate within two weeks at the fairly cool temperature of 60-64°F. Grow the seedlings on at a cool temperature 54-60 °F. Pinch out the growing tips several time to encourage branching, and take the seedlings out into the fresh air as soon as possible. They will tolerate several degrees of frost.
Flowering will then begin in July and continue until well into September. You may, if you like, sow directly out of doors in April-May, but then the plants will not flower until August.
Flowering plants are on sale from April-May, nearly all of them grown from cuttings. Look out for them at nurseries specializing in patio plants. Only purchased plants will show you how inexhaustibly diascias can flower from the day you bought them until early autumn. The plants should be cut back rigorously during intervals between flowering. They will soon sprout again and come into flower a few weeks later. This will prevent the plants from becoming increasingly untidy. They like a sunny position and flower best there, especially in hot summers, but diascias may also be grown in partial shade if need be. Shade and excessive feeding will benefit leaf growth and curb flowering.
In the garden, diascias like loose soil that is not excessively nutritive. The likelihood of the plants surviving the winter will be greatly increased by planting them in very well-drained soil, preferably under the eaves, and at the foot of a south-facing wall. In summer, the plants like moist soil. Diascias are very suitable for planting out in containers. They flower most profusely in poor soil, but only if it is never allowed to dry out entirely.
