From soil to songbirds: Why native plants matter

If you have been reading our articles, you already understand the devastating and costly problems invasive species can create.

Maybe you have already pulled your Burning Bush, and you are working on eradicating a large patch of Periwinkle. If so, congratulations and thank you.

For those of you who are new to our articles, here’s a reminder - invasive plants are non-native plants that cause harm to our economy, human health or the environment; they spread aggressively and displace native species while disrupting the ecological relationships that people and wildlife depend on.

They often naturalize in areas other than our gardens, such as forests and roadsides. It will then take millions of dollars to eradicate these villains.

So, why is it important to replace invasive species with native plants? Why not plant non-native plants which are not on the invasive list? Let’s look at one example: a native Oak tree versus a Ginkgo tree which originates from China.

Native Oak trees support over 500 species of butterflies and moths alone. Compare this to Ginkgo trees, which support at most five species. Over thousands of years, native Oak trees have evolved alongside local insects, creating complex food webs.

Ginkgo trees evolved in China, so our native insects have not had the opportunity to learn how to feed on them and overcome the tree’s chemical defense systems. Various chemicals including ginkgolides and bilobalides in Ginkgo leaves act as natural deterrents that repel most insects and fungi.

Therefore, an Oak tree is a critical food source for birds and other wildlife, while a Ginkgo tree’s resistance to pests is what makes it such a popular choice for urban landscaping and such a poor choice to support biodiversity.

In fact, it takes 6,000 - 9,000 caterpillars to raise a single nest of young chickadees.

So, a healthy insect population is crucial to their survival, and native plants play an essential role by supporting a much wider variety of caterpillars than non-native plants.

This also means birds, especially nesting songbirds, prefer a native tree over a non-native tree because there will be more food for themselves and their chicks.

Now you may ask yourself, are all non-native plants invasive? Absolutely not.

Non-native plants can have a place in our landscape, either based on aesthetics or usefulness. In fact, most of our essential food crops are non-native, yet serve an important role in our wellbeing.

It is alright to have some non-native plants in your garden if you really like these. Just be aware of their shortcomings in the ecosystem and for biodiversity. As gardeners we can make choices to either support habitat for wildlife or contribute to a world where natural habitats are disappearing.

So, what should you do if you have invasive plants? You can make a difference by removing them from your property, so their future spread will no longer be a concern.

Then do the world a favour by planting gorgeous native plants in their place and enjoy watching your garden come to life.

Renee Sandelowsky & Helen Varekamp are volunteers for Canadian Coalition for Invasive Plant Regulation