Naturalization an Urban perspective.

Over the past several years my perspective with regards to food and plants has shifted dramatically in leaps and bounds. From everything ranging from learning about GM foods to opening my eyes to the world of soil microbiology. My most recent eye opening took place this past Thursday evening while attending the first of the Native Plant Talk Series by Dr. Bill Freedman.

Bill is an advocate of what is called urban naturalization, the process of returning urban ecosystems to a relatively high level of ecological integrity. Here are some of the things I learned from his talk.

Ecological integrity- What it is and why it is important.

Ecological integrity is a term used to describe ecosystems that have plenty of indigenous biodiversity, complete food webs, are self-sustaining, have naturally functioning nutrient and water cycles and are resilient and resistant to environmental change.  You can compare this to an urban ecosystem which has little to no ecological integrity, are intensively managed, has very little biodiversity, and nutrients and water are constantly leaving the system, requiring more to be added (Fertilizers). Alien species are the primary cause of low ecological integrity, invasive plants smother the native species, foreign insects kill our trees and even less malign alien species simply don’t provide local species with the sorts of habitats that they require to survive.

There is huge intrinsic value in living harmoniously with natural systems but lets face it, that’s not enough to motivate most people. So what are some of the other advantages of having human populated ecosystems that have ecological integrity?

1)    They require less energy. Trees and shrubs provide cooling in hot climates and seasons and in winter protect building from wind. Many of our neighbourhoods do have plenty of trees and are gaining these energy savings but because the alien dominated urban landscape requires such intensive management these savings are offset. Annual flowers are planted and die every year, shrubs and hedges need to be pruned and manicured, lawns need fertilizing and mowing.

2)    They help maintain high levels of biodiversity. As cities and towns expand and areas of low ecological integrity along with them, we begin to see local species disappear. This may not seem like that big of a deal but imagine a landscape populated overwhelmingly only by species that live around humans, pets and alien plant species. Things like rats, house mice, pigeons, crows, starlings, fleas, bedbugs, flies. In short, things we consider to be pests.

3)    They help save our pollinators. As biodiversity decreases we also begin to see some of our precious butterflies and bees disappear. These pollinators are of course integral to growing any type of plant, including food crops.

Native plants and Urban ecosystems.

So what’s the best way to improve ecological integrity? It’s simple, grow native plants. Native means that the species was present prior to the presence of European settlers, essentially they are species that evolved locally.

Take a look at the plants in your garden, your neighbours garden and our city’s parks. You’ll be hard pressed to find any native species at all. Conventional horticulture relies heavily on pesticides, chemical fertilizers, and plenty of watering. This is because the species of plants that we are trying to grow are not native to this area. Plants that have evolved locally require less care; they don’t need extra watering, fertilizers or pesticides. There are tons of species to choose from, many of them just as attractive as non-native species.

Bill has used his own small urban property as a model for how we might transform our yards from being dominated by alien species to full of low maintenance, beautiful native plants. Here is a video of him and his yard.

Here’s how to naturalize your yard, Bill Freedman style:

1)    First collect and establish native shrubs in your existing yard. Ask around at nurseries, until recently nurseries did not have any native plants, and many still don’t. It’s a good idea to research any plant you find to make sure it is native. Bill says that its not so important that the plant be native to precisely the area you live, as long as they are native to the general area. You can also get native plants from the surrounding countryside, again do some research to make sure the species is native, and of course make sure that it is abundant in the area you are taking it from. You can also start some species from seed.

2)    Once shrubs have been established kill your lawn (oh the horror!) Lay down some wet newspaper and then cover it in 10cm or so of bark mulch.

3)    Plant more native species!

4)    Maintain your yard by weeding out the alien species. This requires you to be a bit savvy in identifying what is native and what isn’t.

5)    Tell people what you are doing! Let your neighbours know, they might not like it but at least they will know why. Tell your friends and family, help them learn if they express interest.

This is of course the most dramatic course of action you can take. You might find it hard to leave the culturally ingrained sense of aesthetic for manicured lawns and flower beds full of non-natives behind. That’s ok! Start by converting your flower beds to native plants, or even just part of them.

Here’s some resources to help you get started:

Native Plant Sources

May 5, 2012. PLANT SALE at the Harriet Irving Botanical Garden

Baldwins Nursery

Millbrook Greenhouses Nursery

Macphail Woods Ecological Forestry Project


Tallamy, D. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. Timber Press.

Cullina, W. (2000) Wildflowers; A Guide to Growing and Propagating Native Flowers of North America. Houghton Mifflin

Sanders, J. (2003) The Secrets of Wildflowers: A delightful feast of little-known facts, folklore, and history.  The Lyons Press

Johnson, Lorraine. (2011) 100 Easy-To-Grow Native Plants: For Canadian Gardens. Whitecap Books

NSAC Native Plant Garden

written by Sebastian Palmer

photos by Rebecca Singer taken at the Harriet Irving Botanical Garden


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