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Archive for September, 2012

Young Ash Tree

A  slight feeling of dread and sadness has been accompanying my walks down my street ever since  I learned about emerald ash borers (EABs).  These small green bugs are  originally from China, and are a blight facing all species of North American ash trees (Fraxinus spp.) They are infecting trees in my own city — Toronto –and in many places throughout Canada and the United States. How long will the beautiful, mature ash trees on my street live?

According to a City of Toronto staff member, because of the emerald ash borer, “Eighty to 95 per cent of the trees [in the city] are projected to die between 2015 and 2017, and from the point of infestation all of the trees will die somewhere between 10 and 12 years.”1

But recently I noticed some signs that gave me a sense of hope for the ash trees on my street, which, I would say, make up about 75% of the tree canopy on my street.  The City has identified 200 locations in Toronto where they will attempt to save ash  trees with a pesticide called TreeAzin.  The trees receiving these treatments are marked with metal tags.2 Most of the ash trees on my street bear metal tags, which I’m hoping signify treatment.

TreeAzin is the only treatment available for EAB and is a natural systemic insecticide made from seeds of the neem tree. It’s injected under the trees bark and kills EAB larvae. It’s quite expensive (up to $500 per tree) and needs to be repeated every two years indefinitely, so it’s not going to save all our ash trees. But it might keep death at bay for many of our trees until more effective control measures are being developed.

And hopefully it can save some of the trees on my street until that treatment is found. Otherwise, the walks on my street will become even sadder as the EAB devastates the beautiful ash trees.

Infected Tree Dying from EAB

Footnotes

1. The Star online. June 9, 2011. ‘Bug 1, Tree 0: Most of Toronto’s ash trees expected to die by 2017’. http://www.thestar.com/news/gta/article/1006004–bug-1-tree-0-most-of-toronto-s-ash-trees-expected-to-die-by-2017

2. ibid

Other Reading

City of Toronto web site:  http://www.toronto.ca/trees/eab.htm

Canadian Food Inspection Agency: http://www.inspection.gc.ca/plants/plant-protection/insects/emerald-ash-borer/faq/eng/1337355937903/1337356019017

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The group of  White Snakeroot plants in my yard this year has created a delightful orb of delicate white flowers. It resembles a bush but it is actually a cluster of single-stemmed flowers.

I strongly recommend this native plant for shady gardens. Mine grows underneath the canopy of a neighbour’s Norway maple, and it has produced a plethora of flowers, starting in late summer, and continuing to bloom in September.

White Snakeroot

White Snakeroot (Eupatorium rugosum) is indigenous throughout southern Ontario in places such as rich woods, thickets, clearings, waste places, ditches, meadows and beside lakes and streams.  I planted mine four years ago and it has formed a clump of plants, about three feet wide and four feet tall in the centre.  The plants get taller towards the centre, which gives the illusion of a shaped shrub.

Do not plant this plant near pastures, however. It’s poisonous to livestock, and will create “milk sickness” in humans when they drink the milk of animals who have eaten the plants.

I think it’s safe to plant this perennial in my city garden, far from any grazing domestic animals. It will spread by seeds, so if you plant this flower, you will be pulling out seedlings. The picture below shows seedlings that grow in the stones surrounding my flower beds. They do not spread by roots, however, so they are relatively easy to control.

Snakeroot Plant Seedlings

Don’t be fooled by the ugly name, the White Snakeroot makes a pretty addition to shady city gardens.

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My hens-and-chicks plant (a species of Sempervivum) had pretty little flowers this summer. But I knew that the plant that bore them was going to die soon.  However, I wasn’t too worried because I also knew that there would be many other little ‘hens and chicks’ that would remain.

Hens-and-Chicks Flowers

I heartily recommend planting Sempervivum in  the most difficult of conditions. They do fine in sandy, dry, soil with poor nutrition. And they spread in neat clumps.  They’re especially great in rock gardens and xeriscaping. Although they’re not grown for their flowers, they are a nice little splash of colour in the spring.  Although the part of the plant bore them will die, if you’ve got a large enough cluster of them, you don’t need to worry, and you can enjoy this  flowery exit.

Dead Flower Stalk

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