Norway Maples: Southwestern Ontario is Under Invasion!

I think it is safe to say that Spring is finally here to stay. Pale feet are peeking out into the world from the freeing comfort of flip-flops everywhere we look. Winter coats have been replaced by light spring coats, or no coats at all. Motorcycles are revving to life, as are a fair amount of lawn mowers.

While they make a heck of a racket, those lawn mowers are a good thing when I see the state of the lawns in my neighbourhood. Now don’t go thinking that I am giving Joe, Bob or Larry a hard time, as that is not what I am getting at. I do not care if Phyllis’ grass is a few inches taller than my own. What I am more concerned about is the little plants in between the blades of grass.  I am talking about all the little seeds that fell in the autumn and are now germinating in the grass. I am talking about Acer platanoides, otherwise known as the common and highly invasive Norway Maple.

Norway Maples – An Invasive Nightmare

Norway maples are indigenous to Eastern Europe, but due to their prolific ways can now be found far beyond their original domain. They arrived in North America in the late 1700s and quickly gained popularity. No surprise, due to their fast growth, brilliant autumn displays, and the ability to grow in areas where other trees cannot. Typically, they can grow in poor soil, dense shade, and are not bothered by urban pollution. While this made it a favourite amongst city planners a few years back, there are several drawbacks to planting this species of maple.

Once you get past the pretty display of yellow and orange maple leaves in the fall, think about the less desirable aspects of this species. Norway maples have shallow root systems that choke out the grass underneath them. Moss may grow, but soon enough, nothing else will. They create a dense shade umbrella overhead as well. This may seem nice on a hot day, but that dense shade effectively cuts off competition due to the inability of light to filter through to other plants. It might not bother you in your backyard, but think about how that affects a forest. Without enough light to support growth, many native species get choked out and die off. Not what we want for proper biodiversity at all.

The other thing that you probably cannot help but notice is the abundance of the Norway maple’s seeds. They produce an awful lot of them. Not only do they produce a heavy scattering of the winged seeds that fly through the air when shed, but these seeds are incredibly hardy. They have an almost 100% germination success rate. That is why when you look at your lawn in the spring, you might see thousands of little maple keys springing to life in your lawn. When you are trying to achieve that perfect astro-turf look, those keys spoil it, I’m afraid.

So while Acer platanoides might still be available at local nurseries to plant in your yard, steer clear of the Norway maples. Instead, rev your lawn mower into high gear and eradicate all of those little trees as quickly as you can. Why not plant a native species instead. How about a nice sugar maple!