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Mosquitoes, Japanese Maples & the Civic Centre

Mosquito control outdoors, caterpillars in a Beech tree, and working with a Japanese maple, plus more on the Civic Garden Centre becoming the Toronto Botanic Garden.
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

June 8, 2003

While I was in Toronto, the time came for our large Rhododendron to be moved to a new position in the garden. It is well over a metre high and much wider than tall. The move was completed success-fully by Yves, and as proof I offer a photo taken from inside the master bedroom looking out at it in full bloom. I think it is one of the old “ironclad” cultivars, ‘Nova Zembla’. The other photo is one of our large clumps of yellow lupins (Lupinus) that not only withstand regular salt spray (they are only a metre from our sea wall) but the deer don’t seem to like them! That’s certainly a plus. If you have deer problems add them to your deer-resistant herbaceous perennial list! Author photos.

Unfortunately for some listener/readers, I find myself with a number of unanswered questions so I’ll try to put that right this week.

Cheryl Vrabel wrote saying, “Last summer I purchased Doktor Doom Residual Insecticide Spray hoping to rid my yard of mosquitoes. Unfortunately I misplaced the sheet with the instructions for spray around the perime-ter of my yard. Can you please advise? I live in Mundare, Alberta and our yard is bad for the little critters this year.”

Though I realize Cheryl cannot hear my AM740 programme, she will be able to pick up her answer on the Website. And, since the mosquito question is so common these days, I decided to in-clude hers and my response in this article rather than just replying by e-mail. The control of mosquitoes with the Doktor Doom Residual Insecticide (in the yellow-label aerosol can) could not be easier. For example, if you want to be able to sit out in your garden without being bothered by the peskies, then just spray the area of grass or patio or deck where you intend to sit, dine or play, and you’ll have effective control for well over a week. In fact, if your area of lawn or deck/patio is in the shade, then the Doktor Doom Residual Insecticide will remain effective for up to two months. But even in the sun, you’ll get control for up to two weeks.

An additional hint from Doktor Doom himself is to cut the grass before applying to a lawn area. That way the application will at least last until the next time you must cut the grass.

Erna Letson, from somewhere in southern Ontario, seems to have a problem I’ve not encountered previously. She wrote: “My Copper Beech of 22 years has had a problem with small caterpillars which feed on the new growth of the tree and leave a whitish film on the underside of the new growth. We have had professionals spray with dormant spray without success and then had insecticidal plugs drilled into the tree also, which helped somewhat but the problem is still there. I have phoned to the University of Guelph and left several mes-sages but they have not returned the call. Do you have any idea where this caterpillar comes from and how do I get my tree free of it?”

I wish I had better news for Erna. There is no easy solution. While not essential, knowing just which caterpillar is attacking the tree would help (it could be the infamous eastern tent, or the lesser-known yellow-necked or hemlock looper; and it could even be caterpillars from the now well-known gypsy, rusty tussock, imperial, leopard or luna moths. However, there are a couple of hints that may help. For example, the time to spray is when you first see the caterpillars, in their smallest stage. One reasonably good control for caterpillars is Bacillus thuringiensis, now generally available in all garden centres. Be sure you get the BTK which is targeted for caterpillars, not the newer BCI formulated as a larvicide for mosquitoes on water. The insecticide Sevin (Carbaryl) is also known to be good on caterpillars and is still available.

As regards your call to the University of Guelph, not knowing whom you called, I cannot help except to say that the office to call for such questions is the university’s Pest Diagnostic Clinic at 519-767-6256 or They make a charge for specimens submitted--$55 per sample, but it is often worth that for an exact diagnosis.

Meanwhile, E. Larkin of Don Mills has a concern about her pine tree, which I think I mentioned previously on my AM740 radio programme. She wrote, “I have a pine about 50+ years old and it looks sparsely branched. This spring it is dropping the ends of branches. Green pieces about 2-3 inches long are falling all around the tree. If anything I would guess a lack of food--it looks sparse even for a pine. Can you suggest something to stop the ends dropping? It is in Don Mills and in clay soil.”

This one is a hard diagnosis, especially when I cannot see the tree! First, all pines like an open, sandy soil, and dislike clay. That said, obviously the tree has been around for 50+ years so it hasn’t done too badly. It may be that it is in decline simply because its roots are not picking up sufficient moisture and nutrients in the heavy soil. I would try aerating beneath the tree and then applying a product such as MYKE Tree & Shrub that may help it. Even though the two may fight one another, I would also try a spray application of a 20-20-20 soluble fertilizer directly onto the needles.

If the falling of the growing tips continues, I suggest sending a sample of a couple of the most recently fallen ones to the aforementioned Pest Diagnostic Clinic.

Des Tierney, a sales associate with AM740 wrote of a concern he and his wife have. Here’s his question: “I planted a small 3 ft Japanese maple last year (full sun) and it is growing nicely. It is growing red leaves every-where but the top of the main stem or branch is bare. Should I snap it off or leave it alone? Also, the branches with leaves are starting to fray out, do I need to tie them closer to the tree with plastic so that it grows up in-stead of out?”

Des should carefully prune off the top main stem if it is dead. To ascertain whether it is or not all he needs do is scratch the branch in several places to see if it is dry and brown or moist and green beneath. Only if it is moist and green is it alive, and this technique will reveal where to cut it--just ahead of a growth bud (or leaf) on the green part. Many Japanese maples did suffer damage this past winter so Des is lucky if he’s only lost a portion of one main branch, even if it is what we generally call the leader.

I would leave the tree to take its own shape, at least initially, unless it’s important that it grow in a particular form or direction. The fraying out he refers to will just make it bushier and that’s likely a good thing. If, after pruning the main stem that appears to be dead, the tree does not have one dominant leader, then prune the side branches all back a little leaving the one nearest to the direction of the original leader to take over. Japanese maples are not normally symmetrical trees/shrubs so I don’t see the loss of the leader as a major problem.

Carol Hallam, a regular listener and high school friend of mine from over 55 years ago, wrote this week as well, commenting on Michelle Landsberg’s article in the Toronto Star last Saturday. She says, “I have just finished reading an article by Michele Landsberg about Edwards Gardens. Did you read it? It paints a very sad picture about the neglected state of the gardens. She mentions the Civic Garden Centre and the fact that it is not in charge of Edwards Gardens. ‘The board of the Civic Garden Centre is about to announce its reincarnation as the Toronto Botanical Garden,’ she says. She goes on to talk about building renovations and expanded library, and that the organization hopes to negotiate a new deal with the city. It's not clear from her writing, but I assume that the ‘new deal’ will put the Civic Garden Centre in charge of Edwards Gardens. Now, my question is: will the name Toronto Botanical Garden refer to both the Civic Garden Centre and Edwards Gardens?”

I did indeed not only read the item, but when I was in Toronto in March I urged Ken Duncan (who Michelle quotes throughout the article) to contact someone at the Star in hopes of getting something published.

Yes, the plans of the folks at the CGC are to include all of the gardens at Edwards with the Centre as the new Toronto Botanic Garden. The idea, in fact, came from the recently deposed executive director, Doug Markoff. There are many, many hurdles to be jumped before anything like what is proposed happens. Not the least is get-ting the facility away from the City’s bureaucrats even though Toronto Council did approve the name change. Bureaucrats and councils are often two different types, with widely different goals. Perhaps the scheme has a better chance of happening now that the city is in such dire straits, finance-wise. The CGC has already raised a considerable amount of the money needed but does have a long way to go yet. Stay tuned!


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