Ivy – Friend or Adversary?
Up until recently I always viewed ivy growing on trees as a parasite, choking the very life out of the defenceless tree. So just how harmful is ivy?
Here are some facts that will help you decide;
- Ivy growing on trees is often thought to be a serious problem, endangering the health of even very large trees. However, its presence on the trunk is not damaging and where it grows into the crowns this is usually only because the trees are already in decline or are diseased and slowly dying
- If the branch canopy becomes thin and allows sufficient light to enter, the ivy will develop into its arboreal form. Fraxinus (ash), a naturally thin, open-crowned tree may suffer heavy infestation, and for this reason ivy on ash trees is often controlled
- When trees grown for their stem or bark, such as birch and some acers, keep the stems or trunks free from ivy
- On other trees, ivy can be allowed to grow on the trunk, although one problem with very old or damaged trees is that the ivy may hide cavities which, in time, could gradually enlarge and possibly affect stability
- Ivy is not a parasite; the short, root-like growths, which form along climbing stems, are for support only. Its own root system below ground supplies it with water and nutrients and is unlikely to be strongly competitive with the trees on which it is growing
Ivy has much wildlife value. As ground cover in woodland, ivy greatly lessens the effect of frost, enabling birds and woodland creatures to forage in leaf litter during bitter spells. Growing on trees, it provides hiding, roosting, hibernating and nesting places for various animals, birds and insects (including butterflies), particularly during the winter months and in areas where there are few other evergreens
Certainly Ivy does serious damage if it gets into the mortar of bricks so if you have it growing on your garden or house wall you should seriously think about getting rid of it. The only way to permanently eradicate it is by use of an appropriate weedkiller. Full details of what are the best weedkillers for this job can be found here.