Hedera helix or common/English Ivy, is a much maligned plant! Often blamed for damaging brick work and strangling trees to death, but is this fact or fiction?
H. helix is England’s only native evergreen climbing shrub, its shade tolerant qualities make it perfectly adapted to its native habitat (dense woodland). Unlike Mistletoe, H. helix is not parasitic to its host plant. Instead masses of almost sticky tiny hair like roots grow along stems for support only. Nutrients, minerals, and water are all provided by its own root system within the soil, not taken away from its host plant. While it may be argued that the presence of another plant so close to a tree makes the relationship between tree and H. helix antagonistic as they both vie for water and minerals form the soil, but any healthy ecosystem can easily support both H. helix and the host tree with no issue.
A dense covering of H. Helix reaching high into the canopy of a tree is not the cause of a trees declining health, but it can be an indicator that the tree is stressed/diseased, as trees which are healthy with a dense canopy will not let sufficient sunlight get to the H. Helix in order for so much growth to occur. Few species such as Fraxinus excelsior (Ash) have canopies which would allow H. Helix to overgrow a tree, so ivy growth may need to be managed to ensure the health if such tree species as F. excelsior.
Far from being detrimental to trees, species of Hedera are invaluable for wildlife, providing a rich source of energy rich food for native and migrating species of birds, in the form of berries in Autumn, any uneaten berries help feed newly born birds in spring. Flowering between September and November, H. helix provides a vital source of nectar for insects ranging from wasps, moths and bees. H. helix also provides habitat and warmth for many species of insects and bats.
One of the only problems with H. helix comes when dense coverings of ivy can hide structural defects or diseases/fungal infections on trees. Cavities or areas of decay may be obscured, leading a tree to become a potential hazard especially during/after heavy storms.
Aesthetic, ornamental and uses of Hedera helix.
As we have seen H. helix is a great addition to a garden for wildlife and nature, so what about your garden? Well this shade loving shrub can provide wonderful ground cover in shaded areas and cover unsightly walls, giving a luscious green covering to plain, boring brick. The two subspecies of H. helix have a very distinct difference, H. Helix spp. hibernica does not climb while H. helix spp. helix is a climber, so if your planting ivy within your garden make sure you pick the subspecies for your chosen location.
Studies have even shown that growing H. helix over houses helps to insulate and reduce energy costs associated with heating! (See this article over on science direct for more information).
Leaves from H. helix start out as dark green 3-5 lobed leaves with the basal two leaves smaller than the middle lobe, as leaves mature they gradually lose the lobes. Flowers on ivy are a wonderful site, with spherical clusters, each one held on a peduncle usually starting from September through to November. Fruits on H. helix are around 9 mm in diameter ranging from yellow/orange to black berries which contain 5 seeds each.
Wildlife and Countryside Act 1981
Damaging/destroying a wild birds nest, whether it is being constructed or has eggs in is a an offence under the wildlife and countryside act of 1981. Also bats may use dense sources of ivy as shelter/roosting sites, so you must be careful before interfering with ivy as the conservation regulations 1994 also make it an offence to interfere with the roosting site of bats.
Peduncle; this is a stem which supports an inflorescence.