Ivy with its propensity to engulf trees and abandoned buildings has made it a target for enthusiastic removal. Yet, more recently, popular opinion is turning in its favour. 

A study commissioned by Oxford University on behalf of Historic England in 2017 provides reassurance. Ivy cannot bore into buildings, and damage where it grows into existing defects can be prevented by careful pruning. In fact, the study demonstrated that ivy has some key benefits to buildings. It buffers extremes of temperature and humidity, as well as reducing severity of frosts. Ivy foliage was also shown to be an effective trap of fine airborne particulates and reduces the amount of pollution reaching the walls.

There are two species of ivy native to Britain, Hedera helix (Common or English Ivy) and Hedera hibernica (Atlantic or Irish Ivy). The latter does not climb but sprawls along the ground. There also numerous garden varieties which have similar characteristics to Hedera helix. Curiously the juvenile growth produces the lobed leaves we all associate with Christmas decorations, whilst the mature growth produces oval shaped leaves. The young growth has flexible stems which produce aerial rootlets which attach strongly but superficially. The mature growth produces more woody self-supporting stems without rootlets. It is this mature growth which produces flowers. The flowers may be inconspicuous to us, but they are a magnet to insects.

Wander past any ivy clad wall or tree on a sunny day in late summer and early autumn and you will see a myriad of bees, flies, wasps and butterflies attracted to the rich nectar and pollen offering. A study by Sussex University in 2013 demonstrated how significant ivy’s presence is to insects. During September and October they showed that the majority of pollen pellets collected by honey bees were from ivy. Hoverflies were also observed to be particularly frequent visitors. Ivy even has its own specialist hoverfly, the ivy hoverfly, and the ivy bee, Colletes hederae, a plasterer bee which specialises on foraging on ivy flowers and was first recorded in Britain in 2001.

Ivy flowers also provide a lifeline to autumn flying butterflies such as red admiral, Vanessa atalanta. A night time foray may also reward you with the sight of moths such as angle shades, Phlogophora meticulosa feasting on the rich ivy nectar.

The wildlife attributes of ivy are by no means limited to the feeding resources provided by its flowers. The holly blue butterfly, Celastrina argiolus, might as its name suggests employ holly for its first generation offspring, but the second brood of caterpillars feed on ivy.

Ivy berries finally ripen in early spring, just as other resources have been exhausted and bird life flocks to these high energy treats. Blackbirds, thrushes, blackcaps and starlings have all been recorded feasting on ivy berries. If lucky, you might see redwings re-fuelling on a cold late winter day.

It is no wonder that the Oxford Study found microclimate benefits from ivy against walls, wildlife has already discovered this. The evergreen foliage makes an excellent early nesting site and shelter from inclement weather for birds such as wrens. Ivy really is a year round plant for wildlife whether it is in town or country.

When is it best to prune ivy?

Our Reserves and Conservation Advisor, Susan Stone, gives her top tips:

"I usually prune mine in late autumn after the ivy has finished flowering. However, in order to leave some berries, I make sure I don’t prune all my ivy at once. I rotationally prune a third each year. For example, if you have three ivy bushes, prune one, or if you only have one ivy bush, prune a third of it. This also helps reduce the weight of arborescent ivy which can be a problem if on walls etc. Ivy is also valuable roosting cover for birds and hibernation for insects, so it's good to not be too drastic. There is some thought that ivy pruned at this time of year can catch the frost, but as we don’t seem to get frosts these days – and my experience is that ivy is pretty hardy – you’d be hard pushed to kill it."

Some useful links:

Ivy on walls 

The honey and the ivy – why gardeners’ foe is the bees’ friend Sussex university 

Pamphlet with main types of insects visiting 

The ivy bee

Ivy factsheet