Cape primroses are cute enough, but there’s also one with a giant leaf
Cape primrose is not the same primrose you would find in the English countryside in spring. This robust flowering plant is from the genus Streptocarpus, and is a close relative of African violet (Saintpaulia ionantha), gloxinia (Sinningia speciosa) and nodding violet (Streptocarpus caulescens), which are all popular indoor plants.
Although they enjoy the same growing conditions, Cape primrose is distinct from its close relatives. Best known are hybrids, developed for their large, attractive, veined leaves that form a rosette for the crowning glory of the plant, which are its stems of large, nodding, trumpet-shaped blooms.
Flowers can appear anytime in warm climates, and are usually seen in spring and autumn in temperate zones. They mostly come in shades of violet but there are also pink, red, white, yellow, near-black, multicoloured and striped forms, and some varieties have frilled or double flowers. Be warned, it will be hard to choose a favourite!
Look for Cape primrose in flower at garden centres (search the indoor plant section), but for the broadest selection of varieties and colours, visit specialist African violet society shows and growers. You can use leaf cuttings to propagate more plants (see overpage). GROWING TIPS Cape primrose plants enjoy a protected spot away from direct sunlight, yet require bright, indirect light for constant growth. They are usually grown as indoor or patio plants. A brightly lit, east-facing windowsill is ideal. They can be grown in all areas, but do best in mild temperatures. LEFT TO RIGHT The giant single leaf of collectable Streptocarpus grandis; a regular Cape primrose with delicate mauve flowers.
Choose a potting mix suited for African violets. Getting watering right is critical. Ensure they are watered sparingly but just enough to keep the mix slightly moist. They don’t mind drying out a little, as they can then fully utilise the moisture around their fine root systems. Apply any liquid fertiliser that’s high in potash (such as African violet fertiliser) about once a month and you will be rewarded with flowers. Lots of them!
In optimum growing conditions, these are long-lived indoor plants. To keep them looking good, remove dead leaves and spent flower stems. Re-pot in spring into a slightly larger pot if the plant outgrows its container. Keep away from heating or air conditioning, and move away from windows if temperatures become cold (especially below 5°C) or extremely hot. COLLECTOR’S PLANTS
If you venture onto the websites of online nurseries that specialise in African violets or visit enthusiasts’ special displays at a collectors’ plant fair, you may find some extra special streptocarpus plants.
My favourite is the giant Cape primrose (S. grandis) – it is high on the must-have list for anyone with an appetite for the truly unusual. Africa has always been rich in incredible flora that appeals to collectors and, true to form, Zimbabwe is the home
of this amazing giant species. It has successfully colonised spaces where many other plants simply couldn’t thrive. Plants cling to life on moss-covered logs, rocks and cliff faces nestled within the understorey of temperate shady forests.
Unlike many Streptocarpus species, the giant Cape primrose is unifoliate – that is, it produces just one large leaf, up to 70cm long. Unifoliate plants are usually monocarpic, meaning they die after flowering, and this is no exception. It takes about two years to mature, then develops a tall, multi-stemmed flower stem with several nodding bell-shaped blooms in a delicate shade of mauve. After flowering, tiny seeds are dispersed over surrounding moist surfaces, where they eagerly germinate into new plants, and the parent plant dies. This is the best way to propagate this plant.
Growing this species at home requires special techniques. Place the young plant towards the side of the pot or hanging basket where the large, handsome leaf can be encouraged to hang gracefullly over the side, so it won’t stop moisture reaching the roots. The roots resent being both too wet and too hot, so a cool, shady corner is needed to ensure a perfect start for a young plant. Although these plants are shade lovers and thrive indoors, they appreciate filtered morning or afternoon sun for a little warmth, but not too much, as they are best grown when temperatures are a mild 21°C.
Choose a mix that is suitable for
African violets (they are cousins, after all) but add about 50 per cent perlite so the root system has good drainage and air circulation, and doesn’t become waterlogged. Avoid the temptation of standing them in a water-filled saucer as this quickly causes the roots to rot.
Although short-lived, the giant Cape primrose is truly worth all the effort of growing it, so you can enjoy a beautiful and rare species at home.