A Watery Fave
A little pond can give you a lot of backyard beautification
By Jeanne Huber
Seven years ago Barbara Ansley and David Vensas of Edmonds, Wash., snaked a hose over a patch of their lawn to outline a pond they wanted to build. Their goals were modest. “We wanted a garden feature,” Ansley says, “a pretty spot where we could sit and feel at peace.”
They adjusted the hose until it defined a pleasing kidney shape, and then they started digging. When the hole was 15 feet long, eight feet wide and in places three feet deep, they installed a rubber liner, filled the depression with water, hooked up a pump and introduced some goldfish. Then came a few weekends of putting plants in and around the pond. Before long, flocks of warblers and tanagers—birds that had never come to their feeders—were stopping by to sip and splash. Dragonfiles buzzed in. Even a leggy heron visited regularly, though it wasn’t entirely welcome, because it speared the fish. Still, Ansley and Vensas got exactly what they wanted: a beautiful backyard pond that transformed their outdoor living.
Although Ansley and Vensas don’t think of themselves as trendy, their embrace of the home-scale pond (also called a water feature) reflects an increasing enthusiasm for “growing” something other than grass, shrubs and flowers. Because ponds can range so widely in size and depth, sun exposure and plantings, and can support different kinds of life both near and under the water, it’s important to have a clear understanding of your goal before you start digging.
“Some people want sound,” says Rick Perry, a Seattle landscape designer and contractor who has been building ponds for 15 years. “But if it’s a gushing waterfall, you might not want it close to your patio. Or is having a pond about seeing lilies or fish? Then you want it near the house. If you want a pond as a focal point for your garden, maybe you want it farther back on the property.”
Sometimes it’s best to start small with a tub garden, which means filling with water anything from a large ceramic pot to half a wine barrel. David Meeks, general manager of Waterford Dardens in Saddle River, N.J., says these miniponds look great with a tropical water lily (which produces showier flowers than hardy lilies) and a few spiky plants, such as papyrus or umbrella palm. To block mosquitoes and keep the water clear, he suggests adding a few goldfish and some oxygenating plants, such as hornwort and fanwort, which grow underwater. A recirculating pump is needed only if you have many fish. “With one or two goldfish, the pond will balance itself out,” Meeks says. “The fish will have plenty to eat. They’ll feed off the plants and eat the mosquitoes.” He recommends red or calico fantails or shubbunkin, goldfish that look like koi. Koi themselves are out unless the tub garden is a prelude to a larger pond, because unlike goldfish, koi don’t limit their size according to the space they inhabit.
For a larger pond, homeowners can use preformed shells made of high-density polyethylene or fiberglass, or they can buy flexible liners of thick rubber or plastic. Concrete is also an option, although a more expensive one.
Preformed shells cost from $40 – $300 and are the easiest to install. You just dig a hole, place the shell, level the edges and fill gaps with sand until everything is firm. Ansley built one pond this way and then went back to liners. “It’s harder to make the edge look natural,” she says of the shells. “Because of the hard edge, things just fall in.” Also, preformed shells offer limited shapes and sizes and come in depths—usually 12-18 inches—that work well for attracting wildlife but can be too shallow for lilies yet too deep for bog plants. Goldfish, however, will thrive.
“Just put in eight or 10, and they’ll keep making babies,” Perry says.
For between 65 cents and $1 per square foot, flexible liners give more leeway to design custom shapes and larger ponds. A seamless sheet can be as large as 50 by 200 feet, although pieces this large are too heavy to muscle into place without equipment. Flexible liners resemble rubber sheeting used on flat roofs, but the material for ponds is nontoxic to fish. Many nurseries recommmend EPDM, a synthetic rubber, in 45-mil (.045-inch) thickness, or Xavan, a new, nonwoven fabric made by Dupont that’s lighter and stronger even though it is generally sold in 20-mil thickness. A PVC liner’s versatility makes it easy to smooth over holes, but it is also more likely to become brittle from exposure to the sun’s ultraviolet rays. With any flexible liner, always use an underlayment to reduce the chance of a tear. Special materials can do this, although scraps of old carpeting also work.
Besides design and size freedom, flexible liners also offer greater choices for depth, creating environments more hospitable to koi. It’s possible to keep koi in a pond 18 inches deep, but professionals don’t recommend it. “With more depth the environment will be more stable,” Meeks says. “Koi tend to produce more wastethan goldfish, and it’s easier to deal with it if the pond is big and deep.” Three feet of depth usually works well, although people who raise show-quality koi dig as deep as six feet.
For a pond’s location, experts suggest areas that receive at least five hours of direct sunlight, the minimum water lilies need to bloom. It’s also important to avoid sites with overhanging trees, because decaying leaves make the water too acidic and rob it of oxygen. Shaded ponds can succeed, however, with the right plants and installation of a mechanical skimmer to sipohn off leaves.
Most ponds require circulation or treatments systems unless the plants and fish are kept in balance. For example, water lilies or floating plants need to shade 50-60% of the water to thwart algae growth. Also key is introducing scavengers such as snails or freshwater clams and the right number of fish, tadpoles or dragonfly larvae to reduce mosquitoes. A good rule of thumb, Meeks says, is to have an inch of fish per square foot of pond surface.
Exceeding that fish limit—or including koi, which tend to uproot shade plants and produce waste that is an unwanted fertilizer—means the pond will need help. You can provide it in several ways. One effective solution is a biological filter, which ranges from $100 to several thousand dollars depending on size. It circulates water over a surface inoculated with beneficial bacteria that turn waste into a plant fertilizer that doesn’t harm fish. Another option is an ultraviolet sterilizer, which uses light from a special bulb to kill algae. It can cost from $100 to several thousand dollars and can work alone in a fishless pond or in tandem with a biological filter when you have fish.
“A UV sterilizer is the absolutely guaranteed way to have clear water,” Perry says. “We’ve never had a customer who wasn’t 100 percent satisfied.”
A koi-friendly pond that measures 11 by 11 feet with a kit that includes a pump, skimmer and a biofiltering waterfall costs about $1,400, Meeks says. Professional installation of the entire pond can add up. Figure on at least $3,500, maybe een two or three times that much, depending on size and other variables.
Linda and John Baumgardner of Harrisburg, Pa., put in a top-of-the-line biofiliter when they had their pond built a year ago, and they’re glad they did. “Other than adding water, the pond hasn’t needed any maintenance,” Linda says. “As soonas you step out, the fish come over. They know you’re there. I just tell people to make their ponds bigger than they think they want. You’ll love it and wish it was more. We have friends who have a pond four times the size or ours, and it’s just magnificent.”
Originally printed in Sports Illustrated, April 22, 2002