Ivy flowers late in the year in November and December, which is a huge benefit to a range of insects (including honeybees) who welcome the rich nectar supply at a time when few other plants are flowering. Sarah Smyth, an Ecosystems & Biodiversity Adviser for Scottish Natural Heritage, explains.
The rich insect life attracted to flowering ivy in turn attracts small mammals and birds when they are trying to put on reserves for the winter. Ivy provides a great home for lots of insects and animals as it provides shelter from frost and hiding places safe from predators. For example, it provides sheltered roosting and nesting sites for small birds such as robins and wrens.
Ivy is a native species and an important part of a woodland ecosystem. It has an unfair reputation for choking and killing trees; this is not true, the ivy will grow up the outside of the tree using it for nothing other than support. The only time ivy can become a problem is when a tree is old or damaged. Deadwood is a very important habitat too (particularly standing deadwood) and one very rarely found in an urban setting.
Ivy is often considered a festive species, like mistletoe. Ivy is not a parasitic species though, so it does not depend on the host tree. The plant is supported by an independent root system that does not compete with the huge network of tree roots, which have the ability to spread further and deeper than ivy. There is a school of thought that suggests that Ivy will actually protect walls of buildings that are in good condition, reducing weathering effects and exposure to temperature extremes. It will penetrate into vulnerable areas, however, such as cracks.
Images: (c) Lorne Gill / SNH except red admiral butterfly (c David Whitaker).