Ivy has a bad name. Many folk believe that it is a damaging parasite that should be removed from our trees. Unfortunately, this is mostly incorrect. Poor Old Ivy is not a parasite. It has its own root system penetrating the soil, from which it gains all its water and nutrients. To help it climb, it also has adventitious roots equipped with small suckers that it uses to cling to its host tree but they do not penetrate the bark. Ivy is just using the tree as a ladder to climb up from the forest floor towards the light and it does not strangle the tree in the process.
For the tree there are some downsides: the extra weight of the ivy on the branches of the tree and the windage of its foliage, which can act like a sail. A healthy tree can normally accommodate these extra loads but in exceptionally fierce weather, or in the case of a diseased tree, damage may occur. In addition, vigorous ivy growth around the tree trunk can produce a localised damp microclimate in which fungal growth can thrive. Tree Inspections become difficult with possible hazards being hidden from sight.
Ivy can grow extremely rapidly, especially on buildings where there is no competing foliage. In a three-year project carried out by English Heritage in conjunction with Oxford University, to determine the true effects of ivy on buildings, the findings were positive. The study showed that ivy covered walls kept the inside of the building 15% warmer in the winter compared to other parts of the structure. In summer, the reverse was the case. The walls were recorded to be 36% cooler!
Ivy also helps to protect and preserve walls from frost, salt and pollution. The only time ivy is not beneficial and should be removed is on buildings that have existing structural damage or crumbling lime mortar because the ivy will creep into cracks and crevices, expanding with growth and increasing the damage and instability.
Value to wildlife
The plant also provides nest sites and shelter for insects, birds, bats and other small mammals. It is an important food plant for some butterfly and moth larvae such as holly blue, small dusty wave, angle shades and swallow-tailed moth.
Due to its autumn flowering, the ivy provides one of the latest sources of pollen, nectar and berries for insects and birds when little else is available. Many insects including, but not limited to, honey bees, wasps, hornets, hoverflies, bumblebees, small tortoiseshells, peacock butterflies and red admirals rely on ivy’s nectar source to survive the late Autumn season. The nectar is an essential part of the ecosystem, providing the reserves needed by the adult red admiral butterfly to hibernate over-winter whilst the high fat content of the berries provides a nutritious food resource for redwings, fieldfares and our resident thrushes as well as blackcaps, blackbirds and wood pigeons. In total the plant can support at least 50 different species of wildlife throughout the year.
Human Health and Welfare
Ivy is known for its many health benefits, as it reduces mould and improves air quality. This is a well-recognised topic at the moment due to a rise in people having respiratory problems. According to NASA, ivy is one of the top air purifying plants, removing toxins like
Mythology and Symbolism
Ivy is commonly associated with Christmas, along with its counterpart Holly. As evergreen species, both plants were used to ‘ward off evil spirits’, with sprigs being picked and brought inside to keep house goblins at bay. It has also been a tradition to place a sprig of ivy within a bride’s bouquet, as it is thought that ivy symbolises fidelity, loyalty and support within a marriage.
Wearing a wreath of ivy leaves around the head was once said to prevent one from getting drunk. The Roman god Bacchus, the god of intoxication, was often depicted wearing a wreath of ivy and grapevines. Ivy was also a symbol of intellectual achievement in ancient Rome and wreaths were used to crown winners of poetry contests. Wreaths were also given to winning athletes in ancient Greece.
Think very, very carefully about the benefits of ivy before you decide whether to remove it.