The Gesneriaceae family appeared in the social register of plant aristocracy when cousin saintpaulia, more commonly called the African violet, became the nation’s number one house plant. Since that time other deserving members of the family, such as Sinningia, achimenes, and episcia, have become better known.
The streptocarpus member of the family makes an exceedingly showy greenhouse plant or a delightful summer bedding plant that, from seed, requires a minimum of 10 months to develop.
We are prone to find fault with the tongue-twisting Latin and Greek names used in horticulture, but, when it comes to describing characteristics, the Greeks had a word for it. Streptocarpus, which is a Greek compound word, means twisted fruit and a glance at the fertile seed pods shows how well it fits. Cape primrose is the common name.
Streptocarpus plants you buy or grow from seed today are in most cases hybrids that have evolved from such diverse parents that an account of their background should prove interesting. On the estate of George Rex at Knysna in South Africa there grew a plant with gloxinia-like flowers.
Seeds of this plant were collected by Bowie and sent to Kew Gardens in England where, in October 1826, the plant bloomed and was given the name Didymocarpus rexii.
In 1828, John Lindley rechristened the plant Streptocarpus rexii, which is now its valid name. This plant had radial leaves and tubular purple flowers with an open flaring lip, set at an oblique angle. This flower formation is very similar to that of its relatives, Sinningia, and achimenes. The flowers were produced on several stems, six or eight inches tall.
Growing Streptocarpus Plants from Seeds
Thirty years later, another streptocarpus, S. woodii from South Africa, was brought to England. This plant was unique in that the flowers were borne on stems that arose from the midrib of its one solitary leaf.
Stranger still, the lone, elliptic-shaped leaf (which was hairy on both surfaces and up to 12 inches long and three inches wide) seemed to be lying on the ground, for the plant had no discernible stem above the soil surface. The flowers were a pale blue and numbered four to 10 on stems which arose successively.
Thus the plant had a long blooming period. A characteristic of the flower, which has had its influence on subsequent hybrids, was the shape of the flaring tube whose three-lobed lip was much longer than the two upper segments.
Shortly after this, a species of streptocarpus similar to S. rexii was brought to England from the Cape region of South Africa. This plant, designated S. parviflorus, had several elliptic opposite leaves, dark green above and white below, about nine inches long and three inches wide.
These leaves rested on the ground or were slightly raised. They were the most striking feature of this species, for they were crinkled like those of the hardy primulas. This gave rise to the common name of Cape primrose, which has become associated with hybrids of streptocarpus ever since. The 6-10-in.
Flower stems of this variety were covered with the reddish hairs which are associated with many gesneriads, while the white flowers, borne in clusters of five to 10, had the characteristic oblique mouth, but were smaller than those of oilier species.
New Streptocarpus Species
In 1884, E. G. Dunn of Cape Town sent seeds of a new streptocarpus species to Kew Gardens where it flowered and became known as S. dunnii. This streptocarpus had one ground-hugging leaf that was two to three feet long and covered with soft hairs.
The brick red-colored flowers were borne in great profusion on one-foot stems and produced over a long blooming period. At Kew Gardens, William Watson began to cross systematically the various species of streptocarpus to produce hybrids that excelled in the species.
Thus, today, we have plants that have large, rich-colored flowers inherited from S. rexii and S. dunnii, crinkled leaves inherited from S. parviflorus, and a succession of flower stapes inherited from S. woodii.
The variations of leaf formation are perhaps the only reason that this plant has not equaled its cousin, the African violet, in house plant popularity. The influence of S. rexii tends to keep the leaves at a reasonable length and radial in formation, but the influence of S. dunnii makes one of the two or more leaves stretch out as long as 18 inches. This presents a problem even in a greenhouse.
Growing streptocarpus plants from seeds are not at all difficult, although the seed is a line like that of most other members of the family. Any good seed sowing method you are now using will probably work very well for you. Plants usually bloom 10 to 15 months after sowing seed, so it is advisable to sow seeds in the summer. The plants are carried through the winter in a 60-degree greenhouse, or it might be easier to buy plants in the spring from a reputable dealer.
Grow Them from Seed
Streptocarpus plants are not at all difficult to grow although, in the seedling flat, they are small and need to be pampered. After several transplantings in successively richer soil, they are ready to be put into three-inch pots.
For this move, use good potting soil which contains a fair proportion of organic material such as leaf mold or peat moss. Shifting to larger pots can be done as soon as there is a firm network of roots showing when the plants are knocked out of the pots for inspection.
Blooming usually starts in May and, depending on the hybrid characteristics, usually continues through August. The plants will tolerate slightly cooler temperatures than other gesneriads, but I grow all of the members of the family in a 60-degree greenhouse except the episcias and African violets.
These genera cannot stand cool weather. The trick, if there is any, to success with the streptocarpus and other members of the family album seems to be in maintaining a moist condition at the roots, without having the soil soggy. They also like a lot of light, but no direct sunlight. They seem to be short-lived perennials that give the best results from new plants each year.
44659 by Cornelius Ackerson