Four berry-rich hollies to plant
‘J.C. van Tol’
Go for this if you’ve only room for one. It will produce lots of berries on its own.
‘Camelliifolia’
A good berrying holly, the glossy-leaved ‘Camelliifolia’ has ruby-red fruits.
‘Belgica Aurea’
Many hollies have variegated leaves, such as ‘Belgica Aurea’ with golden margins.
‘Amber’
If you want to avoid prickles, opt for ‘Amber’, with spineless leaves and deep yellow berries.
Q How do I prune my laburnums to form a tunnel? Keith Stock, by email
A Pruning is best done early in the winter, as soon as the leaves have fallen, which in the south of England is usually November/early December, but you can still do it now. You’ll get the best flowering from young wood and, therefore, it’s important to train in young shoots, and to do so as the growing season progresses while the young shoots are reasonably supple. When the branch system has been formed routine pruning is a matter of simply shortening back sideshoots each year to three or four buds. Shrubs need to be pruned regularly from a young age to avoid large pruning cuts, which don’t heal well on laburnum. Q Why has my apple tree got ‘co on wool’ on it? Esther Hickman, Congleton, Cheshire
A The material on your apple tree is being produced by a sap-feeding insect known as woolly Q What’s stripping the bark from the branches of my conifers? Jo Bunting, by email
A This is most likely caused by grey squirrels. There’s sometimes some feeding activity associated with bark stripping, but at other times it appears to be little more than vandalism! The worst damage occurs at times when the squirrel population aphid ( Eriosoma lanigerum). This tends to infest old pruning cuts and splits in the bark during spring and early summer. Later in summer the aphids spread further over the tree and set up colonies on younger shoots. These younger shoots will often develop a series of soft, white, knobbly growths in the bark as a result of the aphids’ feeding is high and the animal is stressed. If bark has been removed from right around the circumference of a branch or trunk, then the growth above that point will gradually dry up and die.
Unfortunately, it’s difficult to protect trees from squirrels. In time it’s likely that the squirrel population will fall back to a lower level and damage will come to an end. activities. Unfortunately it isn’t as easy to control as other aphids, particularly if the tree is large. It’s best to keep the insect under control during the spring, when the infestations are limited, before it spreads up onto the younger shoots. These will often develop a series of growths in the bark as a result of the aphids’ feeding activities.
Q Can I prune my liquidambar to keep it more compact? John Thompson, by email
A While liquidambar tolerates some light pruning, it wouldn’t be advisable to top your tree. These trees have a graceful, natural pyramidal shape and removing the upper branches of an already mature tree will spoil this, resulting in a squat appearance and uneven growth.
Liquidambars don’t tolerate hard pruning either and it’s also worth bearing in mind that large pruning wounds increase disease risk. If the tree’s eventual size means that you
Q What are the li le green caterpillars a acking the leaves of my citrus trees? Anthony Martin, Rhyl, North Wales
A These are either the caterpillars of the carnation tortrix or the light brown apple moth. Both have small, pale green caterpillars that bind two leaves together with silk threads. This enables them to feed hidden from sight by grazing the inner surfaces of the bound-up leaves. When the caterpillar is fully fed, it pupates within its hiding place. The adult moths are pale brown in colour and can have several need to consider replacing it, you may want to opt for a smaller selection such as ‘Gum Ball’. It reaches 10m (33ft) and is more suited to smaller gardens. generations a year in a greenhouse or conservatory.
The hidden nature of the caterpillars means they’re not readily controlled by pesticides. If the infestation isn’t too extensive, it may be possible to search for bound up leaves and squeeze them together to crush any caterpillars or pupae concealed within.