This week’s posers for Brian
Q: Can you tell me what’s wrong with my acer. It is growing in a large pot. Bill, Bedhampton.
A: Lots of earwigs. Place a small pot with a sheet of screwed up newspaper inside and put this on top of a stick in the compost in the pot. Each morning unwrap the newspaper and give the earwigs a size 10.
Q: The enclosed leaves are from a rhododendron which is growing in a pot of ericaceous compost. There are lots of brown and black markings. Is this a disease and what should we do? BW, Gosport.
A: It is a disease called rhododendron leaf spot. Remove the worst leaves and spray with Systhane fungicide or Roseclear 2 or 3. Repeat in April and the new leaves will be free of this problem.
Q: What is wrong with my white flowering hydrangea? It has lost its colour and lacks vigour. HM, Waterlooville.
A: There is no disease on the plant, but it needs a quick-acting feed. Buy a container of Maxicrop for tomatoes and give it two feeds a fortnight apart. Don’t prune it, just remove the dead flowers next spring.
Q: We have a Cornus Westonbirt which you recommended. This wonderful shrub has brilliant red stems all through the winter. Is it essential to cut it back leaving only 3in of stems in spring or can I leave half of them? GP, Horndean.
A: I cut half the branches right down to the soil level and leave the other half unpruned. Don’t cut off half of the wood on one side, prune out every other one all through the shrub.
Things to do
Reduce the water given to cacti and dust the pads with a small paint brush to smarten them up.
Take cuttings of zonal pelargoniums (geraniums). They root well at this time. Cuttings need to be four or five inches long. Remove any flowers and flower buds and leave just the top two leaves and growing tip. Make a sharp cut below a node and insert into a sandy compost. Don’t over-water.
Try to remove chickweed before it flowers otherwise it will cover the soil in winter. Put these weeds in the compost bin.
Azaleas in pots are now brought indoors. Clean up the plants and give them a good shake. This will remove a lot of dead leaves. They always lose some leaves when initially brought back indoors. Save rain water for watering the pots.
Prune indoor hibiscus as soon as all the flowers have faded. Cut back all the side shoots by half and nip out the tip. Water only when the compost feels dry and don’t feed again until April.
Amaryllis leaves should have died back by now. If not, cut all the leaves off and repot in John Innes No3 compost but no water until you see the flower bud next year. The flower bud will be fat. If watered too soon, there will be leaves but no flower, so wait until the fat flower bud is visible.
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