Documents: Special Interest: Water Gardening:

Water in the Garden
by Gaston Tessier
April 23, 2006


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Photo courtesy of CWF

Water gardening is an area of horticulture that has become increasingly popular. It can be as simple or as complex as you wish to make it — from a half barrel on a patio to a large natural pond.
An attractively landscaped pool becomes a focal point through its ever-changing pattern of reflections, soothing sounds, and movements. A well-designed water feature can transform even a small city lot into an attractive spot to relax and enjoy the outdoors. The secret is to ensure that the pond and surrounding space complement each other and that the pond’ s design and location are in harmony with the rest of the garden and house. Considering how much a garden pond adds to your outdoor environment, the cost is relatively low, especially if you decide to do the installation yourself. 
The ideal spot allows the pond and its associated wildlife to be viewed from inside the house. The chosen location should also provide a nearby sitting area for the enjoyment of the pond’s sounds and beauty. 
Once you have decided on a location, it is time to choose the type of pond. There are many kinds of pre-formed ponds and liners available. Detailed instructions are included with the purchase of these supplies. There are also several books that give step-by-step instructions for proper installation. Check local by-laws before starting in order to avoid costly problems later on. (Some areas limit the depth of a garden pond to 45 centimetres.)
I would like to share some of my personal experiences gained through the creation of a new ecosystem — a garden pond — in my yard. I chose a more naturalistic pond with a curving, irregular shape to fit in with the informal setting of my garden. I softened the edge of a pre-formed pond (180 centimetres long by 90 centimetres wide by 90 centimetres deep) with natural stones and moisture-loving plants, such as ferns, to link it with the rest of my garden. An added waterfall lures birds, such as chickadees and goldfinches, to drink and bathe along the pond’s rock ledges, even though water is already available at two nearby bird-baths. To wildlife, the sound of running water is irresistible. 
A nearby electrical outlet was necessary to power the water pump that re-circulates the pool water and feeds the waterfall. A simple mechanical filter, attached to the pump, prevents clogging by accumulated debris. Additional depth would allow fish and hardy pond plants to overwinter, as long as there were an oxygen pump functioning at all times. The air bubbles would prevent ice from completely covering the surface of the pond. Open areas would allow fish to survive without being poisoned by their own respiration and gases from decaying organic matter. Since the infamous 1998 ice storm and its associated loss of electricity, I am pleased with my initial decision to create a smaller pond. 
The horticulturist in me wanted to grow plants that would not thrive anywhere else in my yard. Therefore, I located the pond in an area with a minimum of six hours of sunlight to allow the successful establishment of the greatest variety of aquatic plants. The following varieties are my personal favourites. They are just a selection of the submerged and floating plants available.

Common Cattail Typha latifolia — a native bog plant, hardy to zone 3, grown in a submerged pot.

Blue Flag Iris Iris versicolor — a naturalized pond plant, potted, hardy to zone 4.

Yellow Flag Iris Iris pseudacorus — a native swamp plant, potted, hardy to zone 4.

Marsh Marigold Caltha palustris — a native bog plant that produces a profusion of shiny, yellow blooms in early spring. Unfortunately, its foliage dies down in summer, so you must combine it with other plants to provide greenery throughout the season. Hardy to zone 4, grown in a submerged pot.

Water Hyacinth Eichhornia crassipes — a tropical floating plant with efficient water-purifying roots.

Shell Flower Pistia stratiotes — a tropical floating plant that multiplies very quickly. It is also known as Water Lettuce. 

Duck Weed Lemna minor — a tiny native floating bog plant readily eaten by goldfish. It also multiplies quickly.

In the fall, after emptying the pond, I bury the potted aquatic plants in the garden for the winter.
To complete my pond ecosystem, I chose fan-tailed goldfish to add colour and movement. (They are also very effective in the control of mosquito larvae.) You may enjoy your garden pool for the sight and sound of water, but aquaticplants and fish will give it that extra dimension. The plant and animal species that share this new habitat will benefit each other. 
The water may turn green shortly after installation of the pond due to the abundant growth of single-celled algae. Initially, water plants are not established enough to shade the water with their leaves, allowing the algae, which loves sunlight, to multiply quickly. As the fish begin to feed on the algae, and the floating and submerged plants compete for the dissolved nutrients and reduce the intensity of light penetrating the pond surface, the green colour will disappear. The leaves of the water plants spread across the water surface, providing shade that slows algal growth, keeps the water cool, and reduces evaporation that may be a problem on warmer days. When this happens, your pond is ecologically balanced. The amount of time required for this transformation will vary, depending on factors such as weather, water chemistry, and pond construction, especially during dry, hot periods. 
The experience of creating a pond in my yard was very rewarding. I continue to enjoy it year after year. I highly recommend it to people wishing to add something new to their garden environments.


Gaston Tessier, who is an experienced biologist and a horticulturist is a volunteer.

Photo courtesy of CWF

Visit the Canadian Wildlife Federation website at

http://www.cwf-fcf.org/

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