Brian answers readers’ horticultural questions
I have several azaleas in pots , each one being about 12in high. One is far taller than the others. Is it best planted in the garden? When, and how high will it grow? JF, Waterlooville.
I think this may be a different type of azalea. It’s best planted in the garden, now. Water well before planting. Azaleas grow best in partial shade. It will probably grow to three feet. Plant in ericaceous compost if your soil is not acid.
Tiny brown eggs are spoiling flowers on my geraniums. What’s causing this and how can I control it? JB, Old Portsmouth.
This is moth poo. You’ll see thread-like caterpillars alongside the veins on the leaves’ undersides. Spray with Pyrethrum liquid after the sun has gone off them.
We have what we think is knotweed growing beside and beneath our shed. How can we eradicate it? BG, Milton.
This looks like Virginia creeper (pictured). Use SBK brushwood killer. Dilute in water and wearing gloves, cover leaves with a wide paint brush. After three days you’ll see the shoots wilting. Repeat.
We have a greenhouse with side panes missing. We can’t replace them because of our age. The roof is perfect. What can we grow for winter colour? J and LT, Cowes.
Winter-flowering heathers, bulbs in pots, pots of polyanthus and cyclamen will provide colour. Cyclamen prefer being cold.
JOBS FOR THE WEEK
Check the greenhouse heater to ensure it will work when needed.
Keep dead-heading dahlias and remove the two little buds alongside each of the centre buds to ensure blooms have long stems.
Keep picking over dead flowers and leaves in the greenhouse to prevent fungal problems.
Water indoor plants less frequently, touch the compost and water only when the surface feels dry.
Try to do some winter digging. Incorporate manure or compost where the potatoes, peas and beans are to be planted.
Remove yellowing leaves on Brussels sprouts. Keep the ground firm and use canes to support plants if you’re in a windy area.
Prick the soil over around spring hearting cabbages and hand-pick caterpillars or spray with Pyrethrum liquid.
Pick up fallen leaves and put them into large former compost bags turned inside out so that you are looking at black bags.
Sort out the strawberry bed. If the strawberry plants are old, there are plants at the garden centres. Why not buy a strawberry barrel, no more weeding through the strawberry bed! Use John Innes number 3 compost for a strawberry barrel, loamless compost is not suitable.
Pick up fallen leaves and put them into large former compost bags turned inside out so that you are looking at black bags. Use one part urine to seven parts water each time you put in a 12in layer of leaves. Close the top of the bag and put a piece of paving stone over the top. This makes leaf mould in a year.
Hand weed in between wallflowers because chickweed soon smothers them. Chickweed grows very fast indeed in October because it is absorbing nitrogen from the soil. Nitrogen is the element that makes plants grow and the chickweed prevents nitrogen from being washed into the subsoil, the chickweed is full of nitrogen, therefore it is a good idea to compost it as long as it isn’t in flower. If in flower, the seeds form in the compost bin and will grow again when the compost is used as a top dressing.