I just came back from an informative day at my annual master gardener's update, and was both impressed and horrified at presenter Gail Wallin's talk about invasive plants in B.C. Gail is the Executive Director of the Invasive Plant Council of B.C. and it was a much-needed reminder to anyone interested in gardening and ecosystems.The long and lovely tradition of sharing plants and seeds across borders and among gardens has led to the spread of invasive plants in our province and across the country.
An invasive plant is defined as not native to the area in which it lives, and harbouring a propensity to take over. Both habitats and species are involved with invasive plants, and it is sobering to think that 50 per cent of all invasive material has been introduced by humans. Invasive plants are the second largest threat to biodiversity in Canada, with development being the number one culprit.Invasive plants harm our environment by out-growing native plants. They generally have no predators so spend more time growing new shoots and spreading thousands of seeds, as well as taking over open ground.Some of the most common invasive plants in British Columbia are Common periwinkle (Littorina littorea), English ivy (Hedera helix), Scotch broom (Cytisus scoparius), Japanese knotweed (Fallopia japonica) and Himalayan blackberry (Rubus ulmifolius).Limited regulation of invasive species and increased imports are two of the main reasons why these brutes are taking over our gardens and wetlandshabitat loss, but B.C. gardeners can help prevent their introduction and spread.Do not purchase noxious weed seeds. Contain creeping plants by growing them in containers. Don't let invasive plants go to seed. Control weeds growing underneath bird feeders. Grow alternative plant materials (the IPCBC offers alternatives to all invasive plants in B.C.). Keep aggressive plants from escaping your garden or landscaped areas. Do not pick plants from the roadside and use them in the home garden, or cut them to put in flower arrangements.Sometimes with even the best intentions, gardeners let invasive plants sneak into the garden. Buy your plant material from a specialty nursery and reputable plant seller. Big box mega stores unknowingly carry many of these varieties due to lack of staff training and information. Wildflower seed mixes may also contain unwanted seed that can potentially harm home gardens and agricultural areas. Read the packages carefully.For more information on invasive plants and complete lists, check out their website at www.invasiveplantcouncilbc.ca.
