I can see the draw of ivy for people who are looking for a lush, evergreen groundcover. Especially one that expands its area of coverage rapidly. However, with ivy I think you get a little more than you bargain for. Unless you are planning to strictly maintain the area that your ivy lives in - look out! Here is a picture I took today walking through one area of Mt. Doug Park. The ivy extends as far as the eye can see, crawling over, and up, anything in its path.
preventing their establishment and spread is key!"
I would encourage anyone who is looking for an evergreen groundcover to consider native plant options first. There are many to choose from and it does not take much research to find the right one to fit your existing soil and sun/shade parameters. Here are a couple of options:
This is one type of Oregon Grape. It is low to the ground, evergreen, has small yellow flowers in the spring and edible, albeit tart, berries in the summer. This plant likes dry to fairly moist soils and prefers shade to partial shade.
Salal is also an evergreen, creeping plant that is very common in coniferous forests. It has small white/pinkish flowers blooming from May to July which yield to dark, juicy, edible berries. It prefers moist, shady areas.
In addition to the plants pictured above there are many varieties of ferns, and other evergreen groundcover that fit different light and soil requirements. I have been incorporating native plants into my garden for the last couple of years and I have also introduced more native plants into the courtyard garden at my childrens' school. I have purchased most of my plants from the Swan Lake Nature Sanctuary at their semi-annual plant sale. If you check out their website they have a great section about native plant gardening and they also offer workshops on the subject in conjunction with the CRD Water Department. I also found a website by Russell Nursery that has a section on native plants with information about size, light requirements, and soil preferences.
I must say that learning about native plants and incorporating them into my garden is one of my favourite things. In fact, if it helps, I would even offer to help plan, and plant my friends' mom's garden to keep her from planting ivy :)