Pond Secrets

If it doesn't already exist in your yard, chances are it's present in your imagination--a sunny pond studded with water lilies and flanked by bog lovers such as cattails and bulrush. Or maybe you have in mind a hidden lagoon with a waterfall off to one side, rocks and ferns placed just so. The foliage of the water lily and other plants helps keep algae at bay, moderates water temperature and provides cover for fish. The largest water lilies have a spread of 12 square feet or more.

Whatever its size or style, a water feature gives the garden an irresistible attraction, adding new elements of sound and reflections to the landscape. But there's sometimes trouble in paradise. Often gardeners have a little trouble getting the new water garden successfully established. There may be problems with algae, muddy water, unhealthy fish.

Creating a water garden, no matter the size, means building a little ecosystem that depends on the interrelationships of the plants and animals that dwell there for its stability. Even a few fish can prevent your pond from becoming a mosquito factory, says water garden expert Charles B. Thomas, but too many fish will cloud the water with waste.

Probably the biggest nuisance is algae, which needs light and nutrients to thrive, but submerged plants, whose foliage grows underwater, are successful competitors. So are water lilies and other floating plants, which deprive the algae of light. And fish eat algae.

There are also steps you can take to stabilize your water. You'll have to make sure the water's pH falls between 6 and 8, dechlorinate the water (if that's a problem) for the sake of your fish, and consider pumps and filters.

All of this may sound intimidating, but it needn't be. Helpful water-gardening books and catalogs spell out easy-to-follow instructions. And once the garden is established, you'll leave it alone and wait until it finds its balance, says Thomas, whose book, Water Gardens (Houghton Mifflin, 1994), written with Jacqueline Heriteau, includes a "magic formula" that prescribes, for example, one bunch of submerged plants and one small floating-leaved plant for every one to two square feet of pond surface.

"People tell me this is the easiest kind of gardening they've ever done," he says. "They can't believe it."

"Start right, and then let nature do its thing," he continues. Constant tinkering--such as adjusting the pH every day--delays the pond's establishing its own balance. Thomas advises patience during the water feature's early days. "Then," he adds, "you can take it easy." Established water features require surprisingly little babysitting.