December 10: Prune wisteria and apple trees; check on Brussel sprouts; prepare ground for spring planting
The desire to get on with the pruning in the garden has not been high, but it has to be done and now is the best time of year for many plants such as wisteria and apple trees, etc. Wisterias are among the most beautiful of all flowering climbers, producing masses of long fragrant racemes of flowers in late spring through early summer, when they are established and growing well. However, they cause a lot of impatient gardeners to despair as they make lots of new lush growth and few or no flowers at all. Wisteria will not flower until they are over five years old and often only flower after eight or even ten years so you will need to be patient. There are a few things that can be done to encourage them to flower well. Throughout the life of the wisteria practice good pruning – this should be done twice a year, as with most shrubs it is good to prune after flowering and again in late autumn or winter. Summer pruning of established plants involves shortening the lateral growths after flowering to 15-30cm from their base on the main framework branches, this will help encourage the formation of flowering spurs, and then in winter cut them right back to just two or three buds. This type of spur pruning needs to be done through the life of the wisteria and it should reward you with a mass of blooms each year. And there are other things to keep in mind if you want to make sure your plant flowers well. Wisterias will grow on almost any aspect, they will flower best if grown on a warm wall in full sun. Avoid nitrogen-rich fertilisers as this will give lots of leafy growth and no flowers. Another method of encouraging plants to flower is to restrict its root run. This can be done by planting it in a large sunken pot or putting a box structure made of concrete slabs in the ground.
•Christmas is approaching, the one time you must eat Brussels sprouts, which always taste better if they have been frosted. As they grow so tall they can be blown around so it is a good idea to check and firm the soil around the base and it may even be necessary to stake, to protect against wind damage. Tall kale and sprouting broccoli should be treated in the same way. Protect the developing curds of cauliflowers from possible frost damage by folding the inner leaves over them. Pick Brussels sprouts when they are the size of walnuts and nice and firm. Leave the tops on the plants until all the sprouts have been harvested and then they can be eaten in the same way as cabbage.
•Having recently visited Anglesey Abbey, a National Trust property at Lode near Cambridge, I was very impressed with the winter garden. Although it was a cold and foggy day the winter garden was full of delights. There are many trees and shrubs that flower during winter, for example Prunus subhirtella 'Autumnalis Rosea', Chimonanthus praecox, Mahonia 'Charity', Lonicera standishii, Viburnum 'Deben' and Daphne mezereum. There are also a large range of trees with interesting bark, for example, Prunus serrula, Acer griseum, and Betula utilis 'Jaquemoontii'.
•Continue to prepare the ground for planting next spring or if the weather is reasonable it is possible for you to carry on planting fruit trees and bushes now. Avoid working on the ground if it is frozen or overly wet.