Foreign weed on $20 Bill


The new Canadian $20 bill is appropriately adorned with symbols of Canada: Her Majesty the Queen, The Peace Tower, the Canadian flag and the Vimy Memorial.

But in a prominent position between the word “Canada” and the number “20”, highlighted by a transparent border, is the leaf of a nasty alien weed-tree, the Norway maple. This tree is taking over Canada’s woodlands and endangering Canadian native trees and flowers. (See CBC article.)

 20 dollar bill with maple design

 Is it really a Norway maple leaf on the bill?

 Professor Julian Starr, a University of Ottawa botanist, is sure that the leaf is from a Norway maple tree. Sean Blaney, a botanist for the Atlantic Canada Conservation Data Centre in New Brunswick agrees that the Bank of Canada has “put the wrong maple leaf on the bill”.

The leaf on the bill has five main lobes, or projections from the body of the leaf, and the tips are thin and hair-like, which makes it a Norway maple (Acer platanoides). The leaves of the native Canadian sugar maple (Acer saccharum) have just three lobes, which have almost parallel sides, and slightly rounded tips. (If you are looking at a real maple tree, the easiest way to tell is to break the leaf from its’ stalk. If white juice comes out, you are dealing with a Norway maple.)

The Bank of Canada dismissed criticisms, saying the leaf is not from a Norwegian maple but rather a "stylized Canadian maple leaf" and does not represent any specific species of maple, but is a blend of many native maple species. This is nonsense to anyone who actually knows the ten native Canadian maple trees; The Sugar, Black, Silver, Bigleaf, Red, Mountain, Striped, Douglas, Vine and the Manitoba maples. However, it seems that no-one with this knowledge works for the mint!


Which maple is the true Canadian maple?

This turns out to be a difficult question. The” indigenous common maple” was used as a Canadian symbol as early as 1700. This was probably the sugar maple. It was certainly not the Norway maple, which was only introduced into Canada in 1778, and was a rare and obscure tree until the mid to late 1800s.

However, the official Heritage Canada web site states that: “It is the generic maple species that is Canada's arboreal emblem”.   However, the familiar maple leaf flag clearly shows a stylized version of the sugar maple leaf.

Why is the Norway maple such a bad tree?

The Norway maple is an excellent tree in its native area of Eastern Europe, where it is part of the natural ecology and where it is kept in control by various pests and competitors from that ecosystem. It’s a problem in eastern North America because it produces thousands of seedlings. Each tree leafs out early, competing with native plants for spring sunlight, and keeps its leaves later into the fall than native maples, allowing it to grow taller faster than native maples. It sucks up more water than other trees, creating a dry shady area underneath its branches where little can grow, resulting in soil erosion. It can end up taking over and eliminating native trees and plants from parks and woodlots. It is such a severe problem that it was declared “Weed of the Week” by the USDA Forestry Service and has been banned in New Hampshire and Massachusetts. The big American Meijer chain has decided not to sell Norway maples, but they are still sold in Canadian garden centres and planted by parks departments.

Sean Blaney says: “It's a species that's invasive in Eastern Canada and is displacing some of our native species, and it's probably not an appropriate species to be putting on our native currency,”

Why does this matter?

Norway Maples would make good ornamental trees if they could be kept in place, but they cannot. They spread like crazy and have become so widespread and pervasive that many people think of them as if they are Canadian natives. In fact they are alien weeds which are taking over natural spaces, the same way as other invasive alien species such as garlic mustard, phragmites and dog-strangling vine are. Most people have very little understanding of, or familiarity with, Canada’s native trees and plants. As long as there is some greenery around them as they jog, cycle or dog-walk through a park, they assume that all is right with the natural world. They have no idea what they are losing, and blithely adopt the leaf a European weed tree as a suitable symbol to place on their currency.

Dr. John Oyston, ODH, a Director of the North American Native Plant Society (, will be giving a talk on invasive plants at Toronto Botanical Gardens on April 17th

Public Web Content Foreign weed on $20 Bill