A much maligned plant, common ivy (Hedera helix) is often thought to be responsible for the death of trees and, as a consequence, is routinely cut back. Ivy is not a parasitic plant however. The fine aerial roots, which people often assume are taking nutrients from trees, are anchors and only penetrate the bark allowing the plant to hold on to the tree. The bark is non living tissue and the ivy does not penetrate the vascular system. Ivy gets most of its nutrients through the root systems which penetrate the ground.
Where a tree appears to be being taken over by ivy is often a symptom of something else happening within the tree, perhaps a fungal infection or simply old age. The tree canopy is reduced by the underlying disease or age and the ivy merely takes advantage of the situation, increasing its own canopy; this adaptation is in part responsible for its bad reputation.
What will cause damage to the tree is when the wind catches the dense foliage of the ivy, so some judicious trimming of the plant can take place. We advise this does not happen in the spring as it will impact on nesting birds. Trimming back can take place in winter, although avoiding fruiting and flowering stems will be appreciated by much of the wildlife in your garden.
Ivy is a wonderful plant for wildlife, the foliage, flowers and fruit provide an excellent refuge for a wide range of wildlife.
During spring ivy provides nesting cover for birds, the dense folliage hides them from predators. The berries appear from November onwards and can still be found on the plant in April, these provide an excellent winter food for song thrush, mistle thrush, redwing, robin, blackcap, collared dove and many more. This is an important winter food which appears when much else is scarce.
Ivy also provides an excellent source of early season nectar, the flowers appear September onwards which gives butterflies and other insects a source of food when there is little else to feed upon. The succession of the flowers through to December is essential for queen wasps' survival.
Holly blue and red admiral butterflies plus many moths are attracted to the flowers and the dense foliage provides a safe winter hibernation area for many butterflies such as comma, brimstone, painted lady and small tortoiseshell.
So please do learn to love this wonderful native species as it brings so many delights to the garden and provides to many in the most bleak of seasons.