So often in botanical circles plants with lovely common names, like shooting stars or Peruvian lilies, have absolutely awful-sounding botanical names. Cape primrose is a case in point. Botanically speaking, it is known as Streptocarpus, which sounds dangerously close to streptococcus, the bacteria that causes strep throat. Some streptocarpus is so beautiful that it will take your breath away, but even it that happens; you will never require a course of antibiotics or a trip to the doctor.
Cape primroses are gesneriads, part of the same family as the common African violet that everyone grows and a few of us actually grow well. The most noticeable difference between the two genera is in size: Cape primrose is usually bigger. The foliage varies as well. While African violets feature velvet-textured, rounded leaves, cape primroses bear elongated, lettuce-like foliage. The leaves, which form basal rosettes, are reminiscent of those of some common primroses. Back in the late eighteenth or early nineteenth century, when the forbearers of today’s streptocarpus where discovered in South Africa, some European plant collector probably saw that foliage and thought of European primroses. Of course that same plant collector may simply have consulted local settlers who had already seen the resemblance and bestowed a familiar name on the plants.
Whatever the origin of the common name, one of the ancestors of the modern cape primrose, Streptocarpus rexii, was introduced to Europe from South Africa in 1826, only nine years before the young Queen Victoria took the throne. Another important species, Streptocarpus dunii, with red flowers, arrived at England’s Kew Gardens in 1886 and triggered a breeding frenzy, much of which took place under the aegis of Veitch’s, an important English nursery. Cape primroses became bigger and brighter, with new colors and color combinations, as well as larger flowers. Even more new varieties were developed in the twentieth century, with advances taking place in the nineteen thirties and nineties.
Cape primrose flowers look very much like large, long-stemmed African violets, except that the petals are joined at the flowers’ bases to form long tubes. The plants flower in many of the same colors as African violets, including a range of whites, creams, near yellows, shades of mauve, purple, pink and red. Many bear bi-colored blooms and some are marked with contrasting stripes or throats. Some, like purple and white ‘Party Pinafore,’ feature ruffled edges and others are absolutely wild, like ‘Spin Art,’ with purple petals, streaked in magenta and accented with white throats.
African violets have always had the reputation of being plants that you can set on a sunny windowsill, water occasionally and forget. Of course, if you do that, the plants are likely to forget you and languish for a good long time before dying ignominiously. Cape primroses have similar tendencies, so it is much better to meet their simple cultural requirements.
When you get your primrose in the mail from a specialty vendor or bring it home from a nursery, inspect for pests or signs of disease. Providing there are none, place in the bright, indirect light provided by a north, east or west-facing window. Set the pot in a tray of water and pebbles to elevate the humidity level around it. This will help elevate the humidity level around you as well, which is generally a good thing, especially in the winter. Refrain from killing your cape primrose from the kindness of giving it too much water. Water only when the top of the soil looks and feels dry and avoid splashing leaves, as it causes unattractive spotting. I use slow-release plant food stakes, which eliminates the need to remember regular feeding, but you can also use liquid or granular products according to package directions.
Beyond those minimal maintenance functions, all you really have to do is deadhead the spent flowers and remove any dying leaves from the plant. If it thrives and produces offsets, gently remove them from the parent plants and pot them up in fresh potting mix in a separate pot. Like the evil streptococcus bacteria, streptocarpus plants can be quite contagious.
If you are actively seeking new and improved strains of streptocarpus contagion, visit any large nursery or garden center. If their supplies are lacking, go to Logee’s Greenhouses, 141 North Street, Danielson, CT 06239, (888) 330-8038, www.logees.com. Free catalog.