Cape Primrose Streptocarpus

Cape Primrose is a genus with over 150 species. The one most commonly known is the African Violet . If you know how to grow an African Violet successfully, you should have success with other species in the genera. The genus name, Streptocarpus, comes from the Greek. Strepto means 'twisted' and carpus means 'seed'. This refers to the twisted seed capsule which is a common trait of the genus.

The plants in this genus are native to warm, moist areas of the world – central and southern Africa, areas around the Gulf of Guinea, Venezuela, Argentina, islands in the Indian Ocean, southeastern Australia, Laos, and Vietnam. They are usually found in mountainous areas.

These plants vary in height and spread from one to one and a half feet. There are trailing varieties that can grow much longer.

These make very good houseplants. Grow them in bright to moderate light avoiding direct afternoon sunshine. They prefer high humidity so you could place them in a tray of water with pebbles. Do not allow the pot stand in water. Water well, allowing them to dry out between waterings. Some species go dormant over the winter. Reduce watering at this time. If the roots are too wet the plants may get root or crown rot. If the leaf edges turn brown, stop watering and allow the plant to dry out completely. This could be a sign of overwatering. Where the climate is warm enough they can be grown outdoors for the summer. They are not hardy below Zone 6.

The plants in this genus are herbaceous perennials grown for their long-lived, showy flowers. The flowers are made up of five petals with one or two petals sometimes fused into a tube. They range in color from red to purple, sometimes with white markings. To maintain flowering, deadhead regularly. When all of the flowers on a stalk have died, cut the stalk back to the base. This will allow room for more flowering stalks to develop.

Their leaves are arranged in a basal rosette or appear singly or in opposite pairs. The leaves are linear or rounded with some being heart shaped. They are usually deeply veined, wrinkled and sometimes hairy. The underside is often a different color. Remove dead leaves by cutting as close to the crown as possible. Trim too large leaves with scissors.

While the plants are actively growing, fertilize with quarter strength tomato fertilizer each time you water. It is better to under fertilize. Too much will cause browning of the leaves. During the winter, if the plant has gone dormant, reduce watering and stop fertilizing until new growth starts in the spring.

Propagate plants from leaf or stem cuttings. They are susceptible to botrytis gray mold so watch carefully. Remove any cuttings at the first sign of mold.

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common African violet diseases and insect pests.