Opening our eyes to plant blindness

By Mark and Ben Cullen

The skeleton of a blue whale creates a jaw-dropping effect. It is hard to imagine a mammal that big, which we did this past summer while the 25-metre skeleton was on display at the Royal Ontario Museum.

At 150 tonnes, a blue whale is hard to beat for bigness. Unless you are looking at a 350-year-old red oak — like the one that grows in a residential back yard in Etobicoke.

Believed to be the oldest tree in Toronto, this Methuselah of trees could tell a lot of stories about our history, if it could talk. Heritage designation was applied for more than 10 years ago on behalf of this behemoth. It still has not been granted.

While we are fascinated with a whale, take it apart and display it in a museum, we have trouble noticing the importance of a tree that is more than twice the size and almost 10 times the age of an average whale.

Botanists now have a term for this: plant blindness.

In 1998, American researchers James Wandersee and Elisabeth Schussler introduced the term “plant blindness.” Studies showed that when people looked at pictures of different landscapes, most would notice animals and other objects before they saw the plants.

“Something that is unappreciated and unnoticed has little value,” says Tony DiGiovanni, executive director of Landscape Ontario, who is determined to fix that.

Landscape Ontario is a founding member of the Green Infrastructure Ontario Coalition (GIOC), an organization that represents the interests of the “natural vegetative systems and green technologies that collectively provide society with a multitude of economic, environmental and social benefits, including urban forests, bio swales, engineered and natural wetlands, ravines, meadows, agricultural lands and more.”

Economic powerhouse

The GIOC provides some numbers to consider:

The green sector employs 140,000 people in both Canada’s private and public sectors. By comparison, Chrysler Canada employs about 11,000.

Consumers spent about $11.7 billion on landscaping and horticultural products last year.

The farm gate value of horticultural trees, shrubs and other plants grown on Canadian farms is more than $2 billion.

DiGiovanni says: “It is the job of our profession to tell our story of benefits in ways that will be heard.”

Last spring, on Mother’s Day, our family gathered at our house for a celebration. We asked brothers-in-law Rene and Martin into the backyard and walked quietly to a 10-metre pussy willow where we all stopped in silence. “What is that?” they said in a loud whisper. We pointed up into the branches of the willow where thousands of honey bees were busy harvesting nectar and pollen. The buzz was deafening.

From that day on, our pussy willow is looked at differently by Rene and Martin. More accurately, it will be looked upon, finally! A large flowering shrub among many others in our 10-acre garden, this tree was easy to overlook until the bees discovered it. And we discovered the bees.

Curing plant blindness

When we find wildlife that engages with the green world around us, we notice the green living world that supports it.

The benefits of green infrastructure are many. Here are just a few:

Green infrastructure often reduces maintenance costs of built infrastructure and extends their lifespans. The shade and cooling effects of mature street trees, for example, significantly extends the life of asphalt roads and concrete sidewalks under their canopy.

Green infrastructure can prevent large-scale damage and reduce costs of floods.

In terms of value, it is hard to overestimate how much money green infrastructure saves us. Here is one number of significance: the Natural Capital Valuation estimated the total value of carbon stored in the Greenbelt in Ontario is $11 billion.

If only we could see the oxygen that we inhale, created exclusively by the green, living plants around us.

If only we could put a value on the toxins that are filtered by lawns and tree roots from rain water.

If only we could pick the fresh fruit from all the trees in our yard.

Perhaps then, we would not be so blind.

– The Toronto Star

Mark Cullen is an expert gardener, author, broadcaster, tree advocate and holds the Order of Canada. His son Ben is a fourth-generation urban gardener and graduate of University of Guelph and Dalhousie University in Halifax. Follow them at, @markcullengardening, on Facebook and bi-weekly on Global TV’s Morning Show.