Please, please stop putting down the lovely Norway maple tree
by Art Drysdale
by Art Drysdale


Art Drysdale, a life-long resident of Toronto and a horticulturist well known all across Canada, is now a resident of Parksville, British Columbia on Vancouver Island, just north of Nanaimo. He has reno-vated an old home and has a new garden there. His radio gardening vignettes are heard in south-western Ontario over radio station Easy 101 FM out of Tillsonburg at 2 PM weekdays.

Art also has his own website at

September 25, 2016

Above, Tony Digiovanni. Below, two shots of typical Norway maples (Acer platanoides), the latter showing the typical yellow-only fall foliage colour.




Over the years (decades!) of writing and broadcasting about gardening and horticulture I have often taken off on those so-called experts that talk or write about what they call “invasive species”. In fact a great deal of money is expended annually by various groups (particularly governments) on preaching to the public about how terrible it is to plants a long list of trees, shrubs and herbaceous perennials that they consider as invasive.

Generally the only response I receive following the broadcast or printing of these what some would call diatribes is complaints and criticism from those who would control what everybody else plants wherever. Seldom do I find other horticulturists agreeing with me; but it does happen. The case I want to write about today is a piece called “Right plant, right place” which appears in the July/August issue of Landscape Ontario magazine. It is written by an old acquaintance of mine, Mr. Tony DiGiovanni who happens to be the executive director of the major trade organization in Ontario, by the same name as the magazine in which the item appears—Landscape Ontario.

Here is what Tony had to say on one of my favourite topics:

“As a rule, I stay away from controversy and conflict. However there are a number of related and increasingly popular movements that need to be examined and challenged. There are native-only planting policies, seed zone restrictions and banning certain trees because of their ‘invasive’ qualities.

“In my view. These ideas and policies are costing the public millions of dollars in failed landscapes. They are also causing serious damage to the environment and reducing biodiversity. On the other hand, perhaps I need to become more aware of differing perspectives.”

Tony then goes on to site some specific examples currently under discussion, the first being the Norway maple (Acer platanoides) debate!

“This spring, a number of volunteers were busy planting 150 trees at the beginning of the Highway of Heroes on Hwy. 401 in Trenton, Ontario. Highway sites are unforgiving. Poor soils, no access to water, salt-spray, compaction and exposed, windy locations makes it challenging for trees to survive. Yet there they were—an oasis of large, beautiful, majestic Norway maple trees, thriving within this harsh climate. The birds were enjoying the shade (so were the volunteers) and squirrels could be seen hopping from branch to branch.

“Amidst the hot asphalt, endless roar of vehicles and unceasing release of dust, diesel, smoke and exhaust, the paradise of Norway maples made the highway tolerable. It would not be out of place to enjoy a picnic under the stately maples despite the severe surroundings.

“Hidden from view, the extensive root systems reach into the soil, relieving the compaction and creating a reservoir of life-enhancing water and air. The leaves silently accept the carbon dioxide from the exhausts and magically and mysteriously convert it into wood fibre, forever trapping the harmful gasses implicated for warming the planet. In addition, the air is cleansed and fine particles of tire dust are entrapped. All these benefits, and yet the Ministry of Transportation will not allow Norway maples to be planted near highways because they are ‘invasive’ and not native. Many municipalities have the same unfortunate policies.

“The emerald ash borer is taking an overwhelming toll on the ubiquitous ash tree. Native-only policies also take a toll. Many native trees do not do well in unnatural conditions found in the urban environment. It is time to re-consider the policies that discriminate against trees that deserve to adorn our landscapes. All trees have their place; native or not, invasive or not. It depends on the site and the context. We need to increase diversity in our urban forest. More importantly we need to plant trees that survive.

“It is time for municipal arborists, landscape architects and others who specify street trees to re-examine ‘native only’ and seed zone restriction policies. It is also time to evaluate rules that limit the use of so-called invasive trees such as Norway maple.

“Invasiveness is neither good nor bad. It is a trait that many plants (native or not) have. Sugar maples are invasive too. The native forest is filled with millions of them. Yet they struggle on highways and in urban conditions—where Norway maples thrive. It makes no sense to eliminate a tree from the planting palette where it does well. We should plant more Norway maples on highways and in cities because success is better than failure.

“Please don’t get me wrong. I am also a strong advocate of the use of natives. I am on the board of Maple Leaves Forever because I believe in promoting the use of native maples. A number of years ago we were involved in a ‘Champion Tree Hunt’ in the Kitchener/Waterloo area. The public was asked to go out and measure the largest trees in their neighbourhood. There were almost 400 entries and it bothered me that most of the winning entries were native trees that are not used by the commercial trade anymore. It was eye opening. As a profession we have moved away from many interesting native species. The current trend towards natives must be applauded, however, ‘native only’ policies should be discouraged. There is no reason to limit our choice. Tree survival should be the priority.”

In the Landscape Ontario article, Tony also writes about seed zone restrictions. I will use that in an upcoming article.


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