Rex Dibley answers Frequently Asked Questions about Streptocarpus plants.
Q. How often should I water my plants?
A. Wait until the compost looks and feels dry or check that the pot feels light. Be careful though not to overwater.
Q. Should I water streptocarpus from above or below?
A. It doesn’t matter! If you do decide to water from below, just be careful that you don’t leave the plant sitting in water longer than necessary.
Q. Where’s the best spot for my plant?
A. Somewhere nice and bright but not in the full midday sun. Just remember that in the wild streptocarpus plants grow in woodlands in dappled sunshine.
Q. What plant food can I use on my streptocarpus plants?
A. A general fertiliser that’s high in potash. A good one to use is Dibleys’ Streptocarpus Food! Because it’s a slow release tablet you only need to place one tablet (two tablets for a large plant) in a pot every month.
Q. Should I start to feed my plants as soon as I’ve potted them up?
A. No. There are nutrients in potting compost that will keep your plants happy for a while. Start to feed them once their roots have filled the pot.
Q. What should I do with my plants during the winter?
A. Give them as much light as possible in a frost free environment. Water infrequently and stop feeding. That is, except for our winter flowering Crystal varieties (such as Crystal Ice). You should keep Crystal Ice and its siblings in the warmth and brightness but unlike other streptocarpus, you should occasionally give the plant a weak feed.
Q. My leaves are turning brown and crispy at the tips. What is wrong and what can I do about it?
A Don’t worry, nothing is wrong! It’s just natural dieback. The leaf continually grows from the base and dies off at the end. Proper feeding will help lessen the unsightliness. If you want you can trim the brown part of the leaf off.
Q. How should I cut off my dead flowers?
A. Remove the individual flowers as they die off and then the entire stem once there are no flowers left on it.
Q. Can I put my streptocarpus plant in a ceramic outer pot?
A. Yes - but it's best to take your plant out when you water it. You have to be careful not to leave your plant sitting in water for any length of time.
Q. My plant has flopped. Why?
A. Either the plant is very dry (solution: water it) or the plant has been over-watered (solution: the roots have become damaged and are unable to function properly. Let the plant dry out completely and it may recover)
Q. When should I pot my streptocarpus up?
A. Usually in the Spring – into an inch (about 2.5cm) larger pot using a peat based potting compost.
Q. Can I split a streptocarpus?
A. Yes, if it has several distinct crowns. The best time to do it is in the spring. Personally, I think that it’s better to take leaf cuttings. They are a safer and easier method of multiplying your plants as you will still have an undamaged original plant if anything goes wrong. Once the leaf cuttings have become established you can then discard the old plant.
Q. Can I use streptocarpus flowers as cut flowers?
A. Flowers of streptocarpus are excellent for cutting: they are long lasting and can be made into lovely displays. The plants have the great advantage that they will go on producing more flowers.
Q. What's the best way to avoid diseases?
A. The best control of fungal diseases is preventative: get the growing conditions right.
- Avoid excessive sunlight which can damage the surface of the leaf, allowing infection to start.
- Always ensure there is adequate ventilation.
- Remember plants do not like to be kept cold and damp.
- Remove dead flowers that fall on the leaves, otherwise the flowers can cause rotting holes in the leaves.
- Never overwater.
Q. Why do the streptocarpus in my greenhouse have long thin leaves and very tall flowering inflorescences?
A. The plants are grown too close together. Keep them well separated, so that the leaves of one plant don't overlap another's leaves.
Q. Which is your favourite streptocarpus species?
A. Species are wild plants and are not of garden origin. They may not be as flamboyant as some hybrids, but they can be very delicate and quite delightful. My favourite would probably be S. candidus because it's extremely floriferous and has a pleasant honey scent.