I do include non-native plants in my garden. After all, I had a lot of them to start with, and it just makes budget-sense to use what you’ve already got. All the plants in my pollinator garden, native or not, must pass a few tests.
Is the plant harmful?
Invasive plants are automatically removed. These are introduced plants that have spread uncontrollably from cultivation into wild spaces. They out-compete native plants and are a significant contributor to habitat loss. Examples of invasive plants in the Ottawa-area include: garlic mustard, dog-strangling vine, European buckthorn, wild parsnip, and Japanese honeysuckle. In my garden, I’ve also pulled out Miscanthus, Japanese barbeary, porcelain vine, and burning bush. For comprehensive information on invasive plants in Ontario, visit Ontario’s Invading Species Awareness Program and the provincial government’s Invasive Species in Ontario page. Remove all invasive plants in your yard to prevent them from spreading elsewhere.
Other harmful plants that are not welcome in my garden are damaging to people. Since a neighbour is allergic to nuts, I won’t plant nut trees whether they’re native or not. I do have a few small beaked hazel shrubs, but they’re far from the property line so nuts won’t fall into their yard. I also pull out any poison ivy, a native plant, that finds its way into my yard. I don’t want anyone to end up with a nasty, itchy rash.
Is it beneficial to pollinators or other wildlife?
I now want plants in my garden to pull their weight. They should provide nectar and pollen in their flowers, have leaves that butterfly and moth caterpillars will eat, or seeds or berries that birds will eat. I also want to add more evergreens for shelter and nesting sites for birds. For example, lesser calamint, which hails from Europe, is an incredibly popular nectar plant for bumblebees and honeybees in my garden . Parsley (Petroselinum crispum) is a host plant for Black Swallowtail butterfly caterpillars, even though it is also from Europe.

Is it just pretty?
Do I really enjoy the flowers or foliage of a plant, even if it is benign but doesn’t benefit wildlife? If the answer is yes, then, I will seriously consider keeping some of it. After all, the garden is for me too. I have a few peonies that I think are spectacularly beautiful and I’m keeping them.
If a plant fails these tests, then it might as well be a plastic plant! Out it goes.