How to look after your Streptocarpus

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To support the images in the Streptocarpus GoYpedia page, I am attaching useful information on the general care of your plants. This information was provided by the British Streptocarpus Society.

CARE OF PLANTS

Coming mainly from South Africa and growing in wooded damp and shaded areas, they get plenty of light but very little direct sunlight. They do not like full sun. If your plants are in the house, the best situation for them is on an east to west windowsill, if in a greenhouse or conservatory you will need to shade most of the time during summer, just enough to keep the full sun from scorchng the plants.

WATER

Summer watering can be twice a day on very hot days but if in doubt, feel the pot weight, this will tell you if the plant requires a drink or not.
Sometimes during summer you may find the plant and the flowers wilting. If this happens do not water until the temperateure has cooled; you will probably find that by mid eening they are all standing up as if nothing had happened to them. They may need a drink they may not.

Winter watering; From November until the end of February they need only to be kept JUST MOIST, this will vary from house to greenhouse (much less in the greenhouse).

OVERWATERING BOTH IN SUMMER AND WINTER WILL CAUSE ROOT ROT AND THE PLANT MAY DIE.

FERTILIZERS

Use any good houseplant fertlizer high in potash at a quarter strength of the manufacturers directions each time you water. Phostrogen or Tomato fertlizer with high potash – it is better to under fertlize as too much may damage the root system and cause browning of the leaves. High potash feed will crease your flower quantity and quality.

PLANT CARE AND CLEAN UP

During flowering take off all dead flowers at least once a week, when the flower stem has finished flowering, cut it from the plant as low as you can to the leaf base. Any leaves that get tatty or too large can be trimmed with scissors to the shape you require.

In the winter, when the plant is almost dormant, take off the leaves that have flowered that year (they won’t produce flowers again) as close to the base of the plant as you can; the stump will pull off about a month later, this will leave room for the new leaves to form for next year’s flowers.

PESTS AND DISEASES

Streptocarpus are not subject to many pests or diseases, and reasonable precautions can prevent most of these. to prevent the leaves from getting brown on the edges keep them away from bright sunlight and do not water over the top of the plant.
Prevention is always better than a cure and today we have Provado. You can water your plants with this and it should keep away greenfly, blackfly, sciarid fly and the dreaded vine weevil for up to six months. As streps. do not need a lot of water at a time, it is recommended you use Provado for two waterings, this will gtive the plant the quantity it requires and you will not over water the plants. You can also use Provado Ultimate Bug Killer to get rid of most aphids, red spide mite, thrips and mealybug, but keep the spray off the flowers.
Other pets such as white fly very rarely attack streps. If on the other hand you are unfortunate and get mealybug, another cure is methylated spirits – just dab on with a cotton wool bud; it takes time but its the best cure known.
Powdery mildew can be treated with Systhane Systemic Fungicide.

POTTING

Streptocarpus have quite fine roots so they require a shallow pot, half or continential pots are the best.

To get as much flower as possible, they have to be pot bound. This applies at every stage of potting on, from the first pot to the last.
For young plants straight off the leaf, start with a 7cm pot, when the plant has a good root system showing at the bottom of the pot they are ready for the next size, 10cm and again, when this is full of root and coming out of the holes in the base they can go into a 14cm half pot; this is usually when the plant is 9 mths to 1 year old.

COMPOST

If you use conventional multi-purpose compost you can add grit, perlite or vermiculite to this. It does help with drainage, about 7 parts multi purpose to 1 part grit etc., but does not stop a waterlogged pot, which results in a dead plant.
Peat based composts seem to suit streps better than any other type but you can use a mix of multi purpose and John Innes at a ratio of 50/50 or 2:1.

COMPOST FOR CUTTINGS

Again, multi purpose compost with vermiculite/perlite at a ratio of 2:1

FEEDING

Plants should be fed from the first week in March up to the end of September, using high potash feed as mentioned above. Also Chempak No 4. Use a good brand tomato food and use at quarter strength at each watering.
Don’t be over generous, quarter strength is ample, it keeps the plant in a constant happy conditon. However, do not use Baby Bio or Miracle Gro, this will only give you good green leaves, and very long ones, with very little flower. They are good for what they are intended for, but not Streptocarpus.

GROWING FROM SEED

The best time to sow seed is from October to December in the greehouse if you have a propagator, or April/May if you are sowing in the house or a cold greenhouse. If you want to grow them in the house during winter you will need extra light.

As the seed is so fine I find a quarter seed tray is best, you can sow it thinly, you can also mix the seed with a little sand; this helps to get a more even distribution of the seed.

Fill the seed tray up to a half an inch from the top, with sieved multi purpose compost, or a specific seed compost.
Water well and place in propagator, covering with a piece of glass or clingfilm, for 24 hours to warm through, also letting the compost settle.
In the house place on a mat (tiles are cold) on the windowsill, or wherever you are going to grow the seed, again for 24 hours so to compost can settle and warm through.

To sow seed, fold a piece of white paper in half. Open it and tip seed into the fold. Now tap the paper over the seed tray. Do NOT cover the seed.

Cover with glass and a sheet of newspaper. Tilt and turn the glass over at least once a day, twice if possible. This is to stop the condensation droplets rotting the seed. If you cover with clingfilm check every 4/5 days.
If the compost dries out, use a sprayer filled with lukewarm water to wet it (using a fine spray) or put the tray in lukewarm water for about 10 minutes, to soak from the bottom.

You should see germination starting within 8-10 days in the greenhouse. It takes a little longer in the house. As soon as you see green dots on the compost, remove the paper. When you can count the seedlings, remove glass or clingfilm. 6-8 weeks after you should be able to prick out into a large seed tray, about 50 seedlings per tray, when they have covered the tray pot up into small half pots (7cm).

From seed sown in October/December you should see some flower by July/August.
From seed swn during April/May you may see flower in the very late autumn but it will most likely be the following spring.

TAKING CUTTINGS

The optimum time for taking cuttings is during July and early August.
First prepare a suitable porous compost, water retentive but allowing the roots to breathe. A suitable mix would be 2 parts multi-purpose compost, 1 part vermiculite (for water retention) 1 part coarse horticultural sand (to aid drainage) If the compost is too dry, spray and re-mix to distribute the water. Fill a suitable shallow pot e.g.5" about 1 inch from the top with compost. Prepare the leaf by cutting it across, into pieces about one and a half inches long , with a sharp blade. You can usually get 4/5 pieces per leaf. Dip the lower cut edge in rooting homone powder – not vital but might make all the difference if your conditions are less than perfect. Insert the cutting into a slit in the ompost at a 45 degree angle to allow plenty of light to be absorbed. Lightly spray to moisten and settle the compost.
Take a piece of clingfilm and stretch over the pot. Secure with a large elastic band. Minimal condensation develops on the inside of the clingfilm compared to glass, so there is no need to turn it. Pots of cuttings ideally root quickly in a propagator but will also root well on a warm window ledge if shielded from direct sunlight. The clingfilm can be left in place for 6 to 8 weeks, till new plantlets appear. To harden off the plants make a slit in the clingfilm and gradually enlarge over the next few days before removing it.
Cuttings taken in July/August are moved to a cooler south facing situation in October and grown on till the following March when they can be potted on into individual shallow pots, about 3-4".

Note: Cuttings taken from September – May need extra heat; from the end of May through to September no extra heat is required.
Cuttings taken in June and July will make very good plants for the following year.
September and October cuttings will be a little later in flowering but should flower by August the following year.

• 11 Jan, 2010
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