For the good of ivy
Why should this climber be so maligned? Robin Page defends his favourite plant
Why do so many sensible people dislike one of Britain’s most beautiful native plants — ivy? “Dig it up.” “Cut it down.” “Poison it,” they cry, as their blood pressure rises, and yes, they have even been known to write letters to The Daily Telegraph complaining about this “parasite and killer of trees”.
But let’s take another look at ivy, the beautiful climbing plant that is also known by its colloquial names of bindwood and lovestone because of its habit of clinging and climbing over wood and stone. It clings so tightly that country lore also suggests that a garland of ivy is an aid to love.
In my winter garden it is the one plant that gives me colour and in a cold wind it also creates shelter. At last, too, I have it climbing up the front wall of my house, and it is very welcome so long as it does not pull my study window out. Its sprawling green leaves are helping to soften the harsh appearance of 1920s cheap, mass-produced brick that my grandfather used when he built this farm worker’s cottage. By letting the ivy grow, I am helping to quash one of the myths about ivy — that it gradually weakens and breaks up buildings, pulling out the cement and crumbling the bricks. This is nonsense. Ivy simply grips, grows and climbs; with good cement and brickwork it causes no damage and actually does the brickwork good by keeping it dry.
Abandoned buildings do get covered with ivy and it seems as if its roots and shoots assist in the demolition process, but in reality many of those ancient buildings were suffering from wind, water and frost damage before the ivy arrived.
In much the same way ivy is said to be a tree killer, by clambering up healthy trees, strangling them and sucking out their sap. The facts are that ivy is not a parasite and takes its moisture and nutrients from the ground, creating little competition for a good healthy tree. It does not “clamber” either, it climbs slowly and will usually take more than 30 years to get near the top of its host. The main threat it poses is during gale force winds when its weight and wind resistance can help bring a weak tree down.
But the real appeal of ivy is as a conservation plant. In the garden, if it is allowed to grow on the ground, its shade will keep out weeds. And where it climbs up trees, bushes and walls, it is a plant to be enjoyed for the wildlife it attracts.
Ivy is one of the last flowering plants of late summer and early autumn. It usually starts in late September and sometimes goes on into November. Its clusters of flowers are rich in nectar and pollen and a host of insects, bees and bugs use them to refuel before winter. A heavily flowering ivy bush can be heard as well as seen as the last of the year’s wasps bumble bees, flies and hornets fly from flower to flower. Late-flying butterflies such as red admirals and painted ladies are also attracted to the sweet feast.
But to the holly blue butterfly, one of the most beautiful butterflies of spring, the ivy is an important food plant. Second-generation butterflies often lay their eggs on ivy. The caterpillars feed on the flower buds in August and September, then hibernate as chrysalises from September to April, when on a sunny day the first blue butterflies of the year will emerge. This spring generation of butterflies will then lay their eggs on holly, which become the second generation of late, summer butterflies. Perhaps it should be called “the holly and the ivy blue”.
The dense leaves of ivy are also a favourite place for hibernating brimstone butterflies, which will leave their winter shelter on a warm day in March. Winter shelter is important for birds too. As I look at the ivy-clad trunk of a silver birch from my study window, I see birds of all sorts seeking shelter on rough days. This shelter continues into the spring and summer when the tangled mass of leaves and branches makes an ideal nesting place for a host of garden birds, including wrens, robins, long-tailed tits, blackbirds, collared doves and wood-pigeons. When grey squirrels moved into one of my clumps of ivy, I have to admit that I did saw through its trunk, but this was a rather extreme way of moving the squirrels rather than protecting the host tree.
Because ivy is late flowering, its berries are just beginning to ripen now, just as the last of the hips and haws have been finished. Perfect timing for wildlife. Any day now, blackbirds and pigeons will begin to gorge themselves on the berries.
As a lover of wildlife gardening and winter green, I welcome the ivy and hope that all those who are excited on seeing their first brimstone butterfly in the spring will remember from where it has emerged.
Host, not parasite: ivy provides food and shelter for wildlife