The Amateur Gardening team take you through how to grow beautiful streptocarpus in all varieties.
Once you’ve grown one Cape primrose successfully you’ll be hooked forever, says Anne Swithinbank.
There are literally hundreds of varieties of streptocarpus and they are very collectable. As the common name Cape primrose suggests, streptocarpus originate mainly from South Africa, where they grow in wooded areas, enjoying moist soil and light shade.
This is an easy environment to replicate indoors. Normal room temperatures are tolerated well, though plants might suffer in hot, dry rooms during winter. Plants can survive cold, down almost to freezing, as long as they are kept on the dry side, however a winter minimum of 7-10˚C/45-50˚F is ideal. I often display my collection in our north-facing porch, alongside potted lilies and ferns.
The biggest danger is overwatering because this kills the roots and causes the plant to wilt badly. Sometimes over-potting adds to the problem and it is wise to leave a plant well alone until it is growing strongly and only then think about giving it a slightly larger pot. Use either a soilless potting compost, or mix in some perlite for a more open texture. Most of us tend to do this by eye, but I reckon three or four parts compost to one of perlite is right.
Healthy plants making active growth should be given a balanced or (when flowering) a high potash liquid feed at a quarter the usual strength at every other watering. Pick off individual dead flowers, and cut out stems when they have finished to encourage the plants to produce more.
Pests and disease
Keep a watchful eye out for greenfly, which sometimes congregate on the flower stems early in the year. Plants may also have problems with mealy bug and root mealy bug.
TOP 3 Streptocarpus
- ‘Harlequin Blue’ is a new introduction from Dibley’s and has two-tone blue and primrose yellow flowers. It was voted Plant of the Year at Chelsea Flower Show – quite an accolade for a house plant.
- ‘Black panther’: Rich, velvety flowers of the deepest purple are hallmarks of this American-bred variety
- ‘Snow White’: This pretty white variety is compact – ideal if you’re short on space
Dibleys Nurseries, Llanelidan, Ruthin, Denbighshire LL15 2LG: 01978 790677 www.dibleys.com
Special Plants: Hill Farm Barn, Greenways Lane, Cold Ashton, Chippenham, Wilts SN14 8LA: 01225 891686 www.specialplants.net