Top 10 Invasive and Horticultural Plants Across Canada

Top 10 Invasive and Horticultural Plants Across Canada

This weeks post is from Council member, Karen Samis, Assistant Professor, UPEI Biology Department

This week, I thought we could focus on the Top 10 Invasive and Horticultural Plants Across Canada. Although I love to see diversity in a garden as much as anyone, we need to be careful to ensure the plants we choose are not also escaping into natural habitats – all the species on this list are or were popular for gardeners at one time or another (many still are) and all have escaped.

Although there are numerous invasive plants in Canada, species on the list (which is soon to be posted on the Canadian Council for Invasive Species website) have been identified in more than one province or territory as a top priority species for gardeners to avoid planting. Of the 86 species on the complete list, none are native in Canada, 34 species are regulated provincially and/or federally (note only purple loosestrife is regulated in PEI), all are invasive in more than one province/territory, and several have also been listed on the IUCN 100 worst invasive alien species list. The top 10 most unwanted plants are listed on six or more Grow Me Instead guides (Yukon, British Columbia, Alberta, Saskatchewan, Manitoba, and/or Ontario, or GMI lists in development by PEI and Northwest Territories).

Here’s the top 10 list, in decreasing order of “importance”. How many have you spotted on PEI?

1. Leafy spurge (Euphorbia esula)
2. Flowering rush (Butomus umbellatus)
3. Oxeye daisy (Leucanthemum vulgare)
4. Purple loosestrife (Lythrum salicaria)
5. Himalayan Balsam (Impatiens glandulifera)
6. Yellow flag iris (Iris pseudacorus)
7. Dalmatian toadflax (Linaria dalmatica)
8. Creeping bellflower (Campanula rapunculoides)
9. Dame’s rocket (Hesperis matronalis)
10. Common tansy (Tanacetum vulgare)

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