Native to South Africa, Streptocarpus – or Cape primrose – are lovely house plants that are grown for their fresh green leaves and pretty, primrose-like flowers in the UK. The flowers come in a wide range of colours, from white to pink, blues and purples, lemon yellow and red; they are often bi-coloured. They bloom from spring though to autumn, offering a long-lasting display. Plants in the ‘Crystal’ series are even more long flowering, and may flower all year.
Streptocarpus are easy to grow as long as a few key rules are followed, and even easier to propagate.
Although having primrose-like leaves, Streptocarpus are not related to primroses. They belong to the Gesneriad family, which also includes African violets (Saintpaulias), and they are cared for in a similar way.
How to grow streptocarpus
The key to growing Streptocarpus is to find a bright window sill away from direct sunlight, and to avoid over-watering. Streptocarpus are native to wooded mountain areas and ravines in South Africa, so thrive in dappled shade, a humid atmosphere and free-draining soils.
Streptocarpus: jump links
- Planting streptocarpus
- Caring for streptocarpus
- Propagating streptocarpus
- Growing streptocarpus: problem-solving
- Buying streptocarpus
- Best streptocarpus to grow
Where to grow streptocarpus
Grow Streptocarpus in a warm, bright spot, out of hot, direct sun – an east or west facing windowsill is ideal. In winter, move to a south facing spot for maximum light.
Streptocarpus need humidity, so a bathroom or kitchen is ideal. Alternatively, stand the pots on a tray of moist pebbles.
How to plant streptocarpus
Plant into a peat-free multi-purpose or house plant compost, in a pot that is only slightly larger than the root ball. Water in, letting any excess water drain away. The plant may take a few weeks to establish.
How to care for streptocarpus
From spring to autumn, water when the top couple of centimetres of compost becomes dry, but don’t allow the pot to sit in water and allow any excess to drain away. In winter, water only when the compost is dry and allow any excess to drain away – the roots can rot in if the compost is too wet.
From spring to autumn, feed every two weeks, with a high potash feed (such as half-strength tomato food) to encourage more flowers. Do not feed in winter, unless you’re growing a plant from the ‘Crystal’ series – feed with quarter strength tomato food.
Deadhead by removing the flower stalks to their base.
Repot every spring, into a slightly larger pot but ensure that the root ball fits snugly in the pot – streptocarpus do best when a little root-bound.
In this video, watch Monty Don repot a streptocarpus and give his advice on Streptocarpus care.
How to propagate streptocarpus
Streptocarpus are easy to propagate from leaf cuttings. Summer is the best time to do it, as plant cells divide quickly, promoting growth.
Select a young, healthy looking, medium-sized leaf. Remove it from the main crown of the plant using scissors or a sharp knife.
Use a clean, sharp knife to cut the leaf into three or four sections. Fill a pot or seed tray with seed and cuttings compost, or mix multi-purpose compost with perlite to aid drainage.
Insert the leaf cuttings into the compost. Make sure you keep the leaf sections the right way up or they won’t root.
Water the cuttings well, then cover with a plastic bag, securing it with a piece of string or twine.
Keep the cuttings in a light, warm place. Baby plants will develop from the base of each leaf after six to eight weeks. After 10 weeks, carefully remove each plantlet and pot it on individually.
Growing streptocarpus: problem solving
Wilting can be caused by over- or underwatering. If the soil feels soggy, you have overwatered. Allow the soil to dry out before watering again. If the plant doesn’t recover, it may have root rot, caused by cold, wet compost – this can be fatal to the plant. If the soil is dry, you have underwatered. Stand the plant in a shallow bowl of water for 20 minutes or so, letting any excess drain away afterwards.
Few flowers and large leaves – the plant is not getting enough light.
Leaves dying back or brown tips on leaves – this is common in winter. Remove any dead leaves and trim off the brown ends with secateurs.
Grey fluff on the leaves is grey mould (botrytis), which can occur in cool, crowded or damp conditions and is often a result of water splashing the leaves when watering or overwatering. Remove any affected areas and treat with a fungicide.
White fluffy spots on the undersides of leaves are mealybugs. Deal with the problem promptly by removing affected leaves and spray with an organic spray based on fatty acids.
Brown patches on leaves could be sunburn – move your plant out of direct sunlight. Brown spots can also be caused by watering with cold water.
Greenfly leave their old, white discarded skins on the flower stalks and leaf bases. Spray weekly with an organic insecticide and use yellow sticky traps to keep them at bay.
Advice on buying streptocarpus
- Make sure you can provide the right conditions for a Streptocarpus – they need bright light, warmth and humidity
- You can often find Streptocarpus at the garden centre, but for the best selection, buy from a specialist retailer
- You can buy Streptocarpus as potted plants, or as plugs, which are smaller and excellent value
Where to buy streptocarpus online
Best varieties of streptocarpus to grow
With an excellent growth habit, Caitlin’s flowers reach over 4cm in size and come in two shades of pink. The Royal Horticultural Society has given it its Award of Garden Merit.
Streptocarpus ‘Harlequin Blue’
‘Harlequin Blue’ was voted RHS Chelsea Flower Show Plant of the Year in 2010. It bears masses of soft purple and pale yellow flowers on short stems, and has a compact habit.
Streptocarpus ‘Harlequin Lace’
Bearing larger than average flowers, each with purple upper lobes and patterned lower lobes in pale yellow and purple, ‘Harlequin Lace’ is an attractive option.
With the upper flower lobes the colour of denim, the lower lobes are more indigo in colour. This is a medium-sized, free-flowering streptocarpus.
Flowers: April – October
‘Sadie’ bears baby pink flowers with a yellow throat and blood-red veins. It’s a particularly striking streptocarpus.
This compact streptocarpus bears large flowers in a deep, purply shade of red, with yellow throat markings.
‘Targa’ is a compact variety, bearing velvety, dark purple flowers.
‘Hannah’ bears baby pink flowers with soft yellow throats, on long stems.
Streptocarpus ‘Polka Dot Purple’
A particularly striking streptocarpus, ‘Polka Dot Purple’ bears masses of flowers with unusual and beautiful purple and white markings. It’s particularly free-flowering and compact in habit.
With bright blue upper lobes and darker markings on the lower lobes, ‘Bethan’ is an attractive variety with a tidy growing habit.
Beautiful bi-coloured flowers of magenta and deep pink.
Streptocarpus ‘Crystal Ice’
White flowers with purple veining are often produced throughout the year.
Flowers: All year