Coastal Invasive Species Committee

header_right_landscape

English Holly (Salt Spring Island Concervancy)

ALIEN PLANT INVADERS

A series of articles on how to identify and manage some common invasive species on Salt Spring Island written by Jean Wilkinson, Stewardship Committee, Salt Spring Island Conservancy.

ENGLISH HOLLY

English Holly and Ivy are often used in traditional Christmas decorations and wreaths, but the plants are very aggressive invaders in North America. They seriously threaten our native forests and can overwhelm indigenous vegetation.

In the winter, why not go out and gather boughs of holly to "deck the halls" for the festive season? By removing holly - especially the berries - from the local environment, you will reduce its spread and impact on native species.

If you don't have an English Holly tree on your property, perhaps your neighbour will share or you can find some along road allowances.

Just be careful that you don't spread the seeds. The berries are toxic to humans, so keep them out of reach of young children. Later, when you're finished with the decorations, place the berries (which contain the seeds) in a plastic bag and dispose carefully in the garbage.

Please don't purchase or plant English Holly and please consider replacing any you may already have with non-invasive alternatives, outlined below.

ENGLISH HOLLY – QUICK FACTS ABOUT A HORTICULTURAL BULLY:

To Identify – Ilex aquifolium - dark evergreen, leathery, alternate, prickly leaves, female plants can produce red berries

-grows 7 to 10 m tall, with smooth grey bark. Caution: can be confused with native Oregon Grape (which has opposite leaflets) or non-invasive hollies. If unsure take a branch to a nursery to confirm species.

Impacts – Grows quickly and casts deep shade, depriving native plants of light, nutrients and water.

Found –in deciduous, coniferous and mixed forests, along edges of wetlands and near residential areas

Spreads – via seeds in the berries (which birds distribute widely), by suckering and by layering

To Control –Pull or dig up small plants when soil is moist. Cut larger plants at the base, below the root crown, and monitor roots and surrounding area for re-sprouting. Keep cutting back until the plant dies.

To Dispose – Put berries into garbage. Stems and leaves can be piled to rot, but watch for re-sprouting and layering.

Alternatives –(grows in *sun, +part shade or # full shade, M prefers Moist conditions, D = Dry, DT = Drought Tolerant)

Native Plants: Tall Oregon Grape *+ D,DT; Red Elderberry + M,DT; Hairy Manzanita * D,DT; Toyon * D,DT; Pacific Waxmyrtle * D,DT; Red Elderberry *+ M,D.

Non-invasive Non-natives: Meserve Hybrid Hollies, *+ M,D; San Jose Holly (Ilex x aquipernyi, with sterile red berries)*; Strawberry tree *+ M,DT; Chinese Holly (I. cornuta) *+ M,DT; Holly-Leaf Osmanthus *+ M,DT; American Holly (I. opoca) *+ M,D; Perny Holly (I. pernyi) *+ ; Pyracantha "Mohave" and "Victory" *+ M,D; Skimmia + M,DT; Berberis x gladwynensis *+ DT; Holly Oak *+ M,DT.

More Info: Salt Spring Island Conservancy Stewardship Committee 250-537-4877, Coastal Invasive Plant Committee www.coastalinvasiveplants.com , Invasive Plant Council of B.C. www.invasiveplantcouncilbc.ca