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 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.
We’ll focus on Ivy in January, but this month, why not go out and gather (not buy!) boughs of holly to “deck the halls” for the holiday season? If you don’t have a holly tree on your property, there are many in the local parks and woods. 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 seeds) in a plastic bag and dispose carefully in the garbage.
By removing holly from the local environment you will reduce its spread and impact on native species, all the while gathering invasive, free greenery to decorate your home! Please don’t purchase or plant English Holly and please consider replacing any you may already have with non-invasive alternatives.

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 – San Jose Holly (Ilex x aquipernyi, with sterile red berries), Meserve Hybrid Hollies,
 American Holly (I. opoca), Perny Holly (I. pernyi), Chinese Holly (I. cornuta), Holly-Leaf 
Osmanthus, Tall Oregon Grape, Red Elderberry, Strawberry tree, Hairy Manzanita, Skimmia, Pacific 
Waxmyrtle, Toyon, Berberis x gladwynensis, Pyracantha “Mohave” and “Victory”
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

Added on December 6th, 2010