Ivy on trees and as a ground cover weed
Much maligned, ivy is often accused of strangling trees on which it grows. The reality is often less sinister and ivy provides shelter for many forms of wildlife but there may be times when its control is advisable. In the border, ivy’s dense growth can swamp other plants and control here is often needed.
Latin name Hedera helix
Areas affected Trees, overgrown borders, rough ground
Main causes Woody evergreen climber with fast, dense growth
Timing Seen year round; treat accordingly
What is ivy?
Ivy is a woody stemmed, self-clinging climber that can grow quickly into the canopy of a tree. Where it grows as a trailing, ground-cover plant it roots in at many points and its stems extend over a wide area. Ivies have enormous value to wildlife, providing all-important year-round shelter for huge numbers of creatures including birds, small mammals and invertebrates. For more on the benefits of ivy and how to grow it, see our page on Hedera.
The botanical name for ivy referred to on this page is Hedera and it includes the native climber English ivy (Hedera helix). These are unrelated to the deciduous climbers known as Boston ivy (Parthenocissus tricuspidata) and Virginia creeper (P. quinquefolia). This page looks at options for gardeners when ivy is becoming a problem on trees or in borders.
How to recognise ivy;
- Ivy is identifiable as a dense-leaved, evergreen climber. In its climbing state it has three- to five-lobed glossy leaves
- Once it reaches the upper parts of a tree’s canopy, ivy often produces shrubby (arboreal), mature growth which bears yellow-green flowers followed by black berries. The leaves are then heart-shaped
- On the ground, ivy forms dense evergreen ground cover with three- to five-lobed glossy leaves
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 crown this is usually only because the trees are already in decline or are diseased and slowly dying.
When to tolerate ivy
- On most trees that are in sound health and are not being grown for their attractive bark, ivy can be allowed to grow on the trunk without concern for the tree's health or vigour
- Ivy is not a parasite like mistletoe and does not penetrate a tree's bark or roots; 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. It is also found mainly on established or mature trees where, unlike young trees, some competition can be tolerated
- 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. The arboreal form is also an invaluable late nectar source for many pollinating insects
When to consider controlling ivy
- If the branch canopy becomes thin and allows sufficient light to enter, the ivy will develop into its arboreal form. Fraxinus (ash) and Larix (larch), are both trees with a naturally thin, open crown so may suffer heavy infestation. For this reason ivy on ash and larch trees is often controlled
- Where ivy may be a problem is with very old or damaged trees. Firstly, its dense evergreen cover may hide cavities or areas of decay. Secondly, it can become an additional weight in the canopy which, in time, could affect stability of the tree, particularly in windy conditions
- When trees are grown for their attractive stem or bark, such as birch and some acers, it is sensible to keep the stems or trunks free from ivy so as not to obscure this key ornamental feature
Note: The presence of ivy often indicates a tree in ill health, infected with honey fungus for example. This should be investigated. If you are concerned about an old or diseased tree, always seek professional advice from an arboriculturist or tree surgeon.
When to control
When undertaking work on ivy check that there are no birds nesting, as it is an offence under the Wildlife & Countryside Act 1981 to damage or destroy the nest of any wild bird while it is in use or being built. The bird nesting season is usually considered to run March to August (though it may last longer for certain species or multiple broods so always check if in doubt).
As ivy is not directly harmful to trees and is beneficial to wildlife, control is not usually necessary. However, where it is undesirable either by obscuring attractive bark or adding weight to an ailing tree, control will be needed. First, consider whether this can be done using non-chemical means such as digging out or cutting through the stems at ground level. Where these methods are not feasible, chemical controls may need to be used.
The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
Where possible, the stems should be cut back to the ground and the woody stump dug out. If proximity to the tree’s roots prevents removal, regular cutting of the stems to ground level may weaken the ivy over time but is unlikely to kill it.
As an unwanted ground cover
Dig up all stems and woody roots. This may be difficult on heavy soils or where vegetation is very dense. Where the site is not needed for planting, an alternative control method is to clear away all top growth before laying weed-control fabric and a 10-15cm (4-6in) deep layer of bark mulch. Leave in place for at least two growing seasons.
Glyphosate and triclopyr: Ivy that is growing vertically can be killed by severing the stem close to soil level and treating the stump with a stump and rootkiller containing glyphosate (e.g. Roundup Tree Stump & Rootkiller, Rootblast Super Strength Total Weedkiller, Doff Tree Stump & Tough Weedkiller and Westland Resolva Pro Tree Stump Weedkiller) or triclopyr (Vitax SBK Brushwood Killer).
As an unwanted ground cover
Glyphosate: Ivy is not easily controlled by means of weedkiller sprays, partly due to the very glossy, moisture-resistant nature of its leaf surface. In this situation it is best to try the tough formulations of glyphosate (e.g. Roundup Ultra or Rootblast Super Strength Weedkiller). It is essential to avoid spray coming into contact with the foliage or green stems of other plants, so cover adjacent plants with polythene, kept in place until the spray has dried. Bruising the leaves by trampling or with the back of a rake prior to treatment may help with the uptake of the weedkiller. Repeat treatment is usually required for good control.
Triclopyr: In rough grass areas, Vitax SBK Brushwood Killer, containing triclopyr, can be used as it should not seriously damage long grass. However, it could affect the developing growing points of bulbs, particularly if applied in late winter, causing foliage and perhaps flower distortion in the season following application. Therefore, if treating areas under-planted with bulbs, avoid run-off into the soil as much as possible.
Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining different weedkillers available for gardeners; see sections 1a and 4)
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