Brian answers readers’ horticultural questions
All our cabbages, kale and Brussels sprouts are smothered with whitefly. How can we prevent this happening next year? We also have a few in the greenhouse. Win and Robert, Fareham.
You can save your brassicas if you spray them with 4oz of soap flakes in two gallons of water. Add hot water to the soap flakes to ensure they melt then add cold water. Use a pump spray on the cabbages and sprouts on a dull day paying attention to the undersides of the leaves. Repeat two days later. In the greenhouse use sticky yellow cards, hang them up and keep shaking the plants and the pests will fly onto the pads. I use both methods and they work.
Where can I buy potting compost with a vine weevil killer included? BS, Locks Heath.
This compost has been discontinued. Your best plan is to plant up the containers and once the plants are established drench the compost in the container with Provado Vine Weevil Killer. Trappit barrier glue can also be used as a two-inch wide band around the outside centre of each container. In addition to this, keep the foliage a few inches from a wall. Luckily wine weevil adults can’t fly.
I have brought my potted tibouchina shrub into a lean-to for the winter. Will it be OK? MS, Anchorage Park.
Thanks for sending the above picture. It looks wonderful. If the weather gets really cold it will be a good idea to bring it indoors and keep it in a light place.
JOBS FOR THE WEEK AHEAD
Have a look at the garden centre and you will see some lovely azaleas in pots. If you feel you are not green-fingered, think again, these gems will do well in your home. Choose the one you like, it will have just one or two flowers open when you choose it with lots of flower buds at the tips of the stems which will bloom in the coming weeks. That’s the one to buy! They love rainwater. Keep the plants in a light, cold place, just a few degrees above freezing. A window is ideal, but not in direct sun. It’s a pity they don’t have a perfume. I love azaleas.
Bush roses need to be reduced in height to prevent the plants rocking in the wind. Allow the last flower buds to open and then reduce the shoots by about a third. Cut back to a bud facing out of the bush.
At this time of year, all rose bushes would appreciate a top dressing of well-rotted manure applied at a thickness of about three to four inches over the surface of the bed. Remove weeds before applying the manure. Well-rotted farmyard manure is available in large plastic bags at all garden centres. This is better than home-made compost because the manure is weed free.