Documents: Special Interest: Water Gardening:

Garden Ponds My Comments After 16 Years, Part I
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 6, 1999

Water Gardening has become such a huge topic, that my comments on just some of its aspects will be of such a length that they will stretch into at least two of these weekly items.

I still hear it said, that algae in garden ponds is easily eliminated by blah, blah, blah! It seems everybody has a quick fix for algae these days. Right from the first radio items I did on water gardening in the spring of 1983, and the article I wrote on the topic for the Toronto Star April 1, 1990 (which, humbly [!] I say began the re-popularization of water gardening) I have been advising folks not to take the obvious quick fix for algae - draining the pond, and refilling with clean water from the municipal system. That simply makes things worse. Now however, there seem to be more quick fixes than ever out there, being suggested by many people who don't really understand the dynamics of an outdoor pool.

One noted horticulturist, several years ago prescribed all the usual suggestions to a query about algae. He wrote about oxygenating plants, floaters like water hyacinth, trapdoor snails, patience while the pond "adjusted" and other standard recommendations. What he failed to tell the reader was that it is necessary to have at least 70 percent of the pools surface covered by water lily foliage. Some people, when told this, will say that flies in the face of the recommendation that water ponds be located in full sun locations. (A sunny location is a must if you want to be able to grow any number of water lilies at all. There are two or three water lilies that will grow in a slightly shaded environment, but only two or three, and there are many other water plants [not lilies] that will grow in shade). The advice of 70 percent coverage of the water surface with lily foliage is, in my opinion, the single most important piece of advice you should consider.

While the lilies need the sun in order to produce flowers, the water is better if it is not exposed to an excess amount of sun - which only speeds up algae production. Good coverage of the water surface with lily foliage is the single greatest aid to preventing algae growth. I wish that more pond "experts" realized that.

In the last five years, the number of pond treatments, and companies offering them has blossomed in much the same way as the overall "water garden industry." Moore Water Gardens in Port Stanley, Ontario - the original and virtually only people in this "industry" when I started talking and writing about it - still stick with their basic recommendations. They are: oxygenating plants, water hyacinths, scavengers such as trapdoor snails, adequate water lily foliage cover, possibly Sera pond peat, and no chemicals.

At the other end of the spectrum are newer companies such as Aquascape Ontario who seem to include, as a matter of course, such items as a "skimmer bucket which, besides housing the pump, continuously sweeps the surface clean, disposing of debris in a catch bag for easy removal." They also include, at the opposite of the pond, "a bio-falls, a preformed, leak-proof waterfall unit that encourages the production of microscopic bacteria which also helps to control the build-up of unsightly bacteria."

For over a decade I maintained my water garden basically using Moore Water Gardens recommendations and that included no chemicals. More recently, I've tried the "chemical route" and I like the results, but there are many cautions. Ill tell you about my experiences next week.

Last week I wrote about the tough problem of growing anything under a maple tree. E-mail correspondent, Wendy Herron, wrote to advise that she had solved the problem with Lamium, Hosta, forget-me-nots and wild violets.

"The secret to my success was patience. Because of the problems I encountered inter-planting amongst maple roots, I bought plants in the tiniest containers available from my garden centre (so that I would not have to dig big holes) and I waited for them to grow. It took about three summers for my tiny Hosta to mature into full size mammoths but it was worth the wait (and saved me a lot of money). The Lamium is a perfect plant for the large rooted maple because it spreads by runners and loves shade. The wild violets are prolific self-seeders. I transplanted one small sprig of forget-me-nots and over the past three years they have filled in quite nicely and make a very attractive compliment to the Hosta."

"I thought I would have a problem with my plants obtaining sufficient water competing with the maple but I find I only need to water the garden occasionally (every 10 days or so - even with our recent drought) and my Lamium and Hosta thrive."

Now, for those of you who have this maple tree roots problem, please be aware that not everyone will have the same "easy success" that Wendy had. The roots of many really old trees, depending on species, do not even allow for tiny holes to be dug in between. But her ideas are nevertheless sound.

By Art C. Drysdale, 6 Nesbitt Drive, Toronto, Ontario M4W 2G3Art Drysdale is seen hourly every day on Canadas Weather Network at 23 minutes after the hour, and heard Saturdays from 9 to 11 am, with a live two-hour radio broadcast on Toronto's TALK640 (640 on the AM dial)

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