Ivy Hedera helix

Ivy is a native, evergreen climber which has enormous benefits for wildlife especially during the cold winter months when it provides natural shelter for a wide array of mammals, birds and invertebrates.
 
Ivy is also an important food plant for many species. Its autumn flowers followed by ripened berries in late winter/early spring provide an important food source for many insects and birds at a time of year when other natural food supplies have been consumed.  

Picture by Elizabeth Dack
 

Ivy is not parasitic. It has its own root system, deriving its own nutrients directly from the soil. The tiny, root-like structures on its stems merely enable it to cling to the tree without damage to the bark. In rare instances, ivy may cause the toppling of a dead or rotten tree if excessive weight of leaves and stems near the tree’s crown make it top-heavy and cause it to blow over in high winds.

Ivy tends to grow well on trees that are already in decline. A tree in full vigorous growth will not usually allow sufficient light through the canopy for ivy to thrive. Oaks in particular naturally shed branches and limbs as they age. This is an entirely natural process. The dead wood so produced is in turn extremely valuable for wildlife: it becomes a food source for insects, which form a valuable food source for birds such as woodpeckers, while rot holes in dead wood are used by a wide range of species as roosts and nest sites.

Picture by Elizabeth Dack