There are more than 50 species of Diascia, widespread throughout South Africa, and many have horticultural potential. The genus may be divided roughly into annual species which tend to occur in the western, winter rainfall parts of the country, and perennial species in the eastern, summer rainfall areas. These plants thrive in Highveld gardens provided they are given enough water. They also do well in the mediterranean climate of the Western Cape, provided they receive adequate water in summer. They are hardy enough to grow out of doors in milder areas of Britain too, where several hybrids have been bred. Diascias are some of South Africa's most attractive soft perennials and annuals. Diascia interregima is another species frequently cultivated in gardens.

D. rigescens is a showy perennial herb that grows up to 600 mm tall. Several stiff, four-angled stems grow from the crown. The specific name "rigescens" is Latin for "rather stiff" and refers to the stem. This plant may also sprawl down banks or over rocks. The upright stems are less branched than those that are sprawling. The leaves are simple, sessile, thick-textured, heart-shaped, opposite and have sharp little serrations along the margins. The leaves are mostly crowded at the base of the plant, becoming more sparse towards the top.

Flowers are carried in loose clusters and vary from pink to rose with a deep rose throat. They are especially adapted to attract oil-collecting bees. The main flowering time is summer, although flowers may appear throughout the year. The flowers last well in a vase, but become pale if they open indoors. The fruit is a dry capsule, which contains many small brown seeds, which are approximately 1.5 mm long.