Backyard

Homegrown Wetlands 

For less than $250 you can construct an ornamental water garden that will also serve as a magnet for a variety of wildlife. 

By John Manuel

It wasn’t easy taking that first jab with the shovel; I value my lawn. But I wanted a water garden in my North Carolina backyard, and that meant digging a sizable hole. The second spade of dirt came more easily, and by the end of the day I’d carved out a 5- by 10-foot crater that was 18 inches deep. The next day I laid in a rubber liner and cemented it in place with a flagstone border. I filled the hole with tap water, placed potted aquatic plants on the bottom, and sat back to watch my creation bloom. But a funny thing happened on its way to becoming a garden: Wildlife began to appear. These days it’s the frogs and the dragonflies I watch for. My backyard has become a miniature wetland.

Until recently, water gardens were an uncommon part of the American landscape. They were associated with the formal gardens of the rich, and being made of cement, they were relatively difficult to build and maintain. But with the advent of durable plastics and rubber liners, it’s now possible to build and plant a moderate-size garden for less than $250 that will last 20 years or more.

As the name implies, water gardens are designed principally for growing aquatic plants. There’s nothing more striking than a pink-and-yellow water lily set against the black surface of a pond. I planted water lilies on the bottom of my pool, and irises, horsetails, and dwarf papyrus plants on the underwater shelves. Add to these arrowheads, canna plants, and water poppies, and
you have reason enough to embark on this project. But as I discovered, a water garden–even in the midst of a city like Durham, where I live–also serves as a magnet for an incredible variety of wildlife. It not only adds a lively dimension to your backyard, it also provides a home for globally declining populations of amphibians.

Many of the animals one can expect to find in and around a water garden are transitory, stopping by for a drink or setting up residence just long enough to mate and lay eggs. Birds, of course, are a sure thing. All the common perching birds–robins, cardinals, grosbeaks, blue jays, warblers, and wrens–will use a water garden for drinking. Hummingbirds are drawn to flowering bog plants, particularly the cardinal flower. Larger water gardens–at least several hundred square feet–may attract various species of herons, particularly if the ponds are stocked with fish.

Flying insects will arrive within days, the most prominent being dragonflies and damselflies. These are among the many small creatures we tend to ignore on our outings in the wild, but they can provide hours of entertainment when observed on the intimate scale of a water garden. Notice how the dragonfly hovers in midair, then makes sudden, unbanked turns as it darts after flying prey. The dragonfly does this, I learned, by using its wings in the manner of a rower who turns a boat by pushing on one oar while pulling on the other.

Water striders are another insect sure to delight the patient observer. They can not only walk on water but also jump several centimeters straight into the air and come down without penetrating the surface. Over time, water striders will be joined by large, handsome fishing spiders. Whirligig beetles and various diving beetles may also appear.

Mosquitoes are a frequent concern of people who want to build a water garden, but they are less of a problem than one might think, especially with gardens that have established populations of predators. Dragonfly and damselfly nymphs will devour mosquito larvae, as will fish and tadpoles. If all else fails, you can buy mosquito dunks–solid, doughnut-shaped larvicides that kill mosquito larvae without harming any other life.

A water garden is sure to attract amphibians as well as birds and insects. Green frogs are generally the first to arrive, traveling overland on rainy spring nights by following ditches and rivulets of water. Bullfrogs are drawn to water gardens too. With their booming voices and devilish golden eyes, they are a commanding presence in a small pond.

Toads, which need water in which to mate and lay their eggs, are common visitors in the spring. East of the Mississippi River you will most often see two species. The American toad breeds in March and April. Its song is a long, pleasant musical trill. The Fowler’s toad breeds from May through July. Its song is a harsh waah sound.

My favorite amphibian is the gray tree frog, which is often heard but rarely seen. Gray tree frogs are small and well-camouflaged, and they live high in the trees except when they come down to the water to mate, between early May and late July. Their whirring song fills the night in spring, allowing me to believe I’m somewhere far away from the suburbs.

Another common but rarely seen amphibian visitor is the spotted salamander. These large black-and-yellow creatures, seven to eight inches long, come to water gardens at night to lay their eggs. Salamanders must be able to get in and out of the water, so they need dangling vegetation around the edge of the pool or a board angling into the water. Fish eat salamander eggs, so be aware that you can’t have both.

Occasionally one will find snakes in and around a water garden. Jesse Perry of the North Carolina Museum of Natural Sciences says the most common visitor is the harmless, land-dwelling garter snake. "I’ve been surprised by how much they love water," he says. "You can get colonies of them living around a water garden."

Many people feel that a water garden is not complete without goldfish or their pricey cousins, Japanese koi. These fish add motion and color, and they eat both algae and mosquito larvae. But too many fish will cause nutrient overload, which leads to green slime. And they will eat the eggs and larvae of amphibians, thus reducing the variety and density of wildlife. If your preference is for native creatures, I recommend against stocking fish.

Mammals of all kinds will use a water garden to drink, although you may not see them during the day if your pond is close to the house. Judging by the footprints in the snow, squirrels, rabbits, foxes, and raccoons have all visited my water garden at one time or another. Some people report that raccoons climb into their water gardens and overturn plants in search of fish, frogs, and snails,
but this is not a problem I’ve had. If raccoons did appear, I would have to dig the garden at least 18 inches deep on all sides, which would mean eliminating the shelves on which my irises and other bog plants sit.
 
 

Building Your Garden

To build a water garden you will need a shovel, a mattock, a square-tipped spade, and a carpenter’s level. The mattock is useful for breaking through tree roots and rocks, and the spade is needed to smooth the sides. You will want to make sure the rim of the water garden is level all the way around, to avoid leaving the liner exposed on any one side after it’s filled with water.

The first step in installing your water garden is to choose a level site that gets plenty of sun. Water lilies need at least six hours of sunlight a day, and frogs and other creatures crave sun as well. Avoid locating your water garden under trees or in a low spot that might fill with silt and leaf litter after a heavy rain.

Outline the desired area, and start digging from the inside out. The bulk of the hole should be 18 to 24 inches deep (18 inches is sufficient for fish and aquatic plants to overwinter in most of the United States), but you will want to leave a 9-inch-deep shelf on which to set bog plants along at least one edge. Once the hole is complete, pack the bottom and the sides with wet sand. Lay in a preformed pond or a flexible liner, and fill it with water.

Many garden shops and building-supply stores now sell prefabricated ponds made of polyethylene plastic or fiberglass. Often sculpted in natural-looking shapes, they vary in size from about 125 gallons (roughly four feet by six) to 950 gallons (roughly six feet by eight). Prices start at about $50 and range up to $1,000. The life expectancy for top-of-the-line fiberglass ponds is 50 years.

A flexible liner is more versatile than  a preformed pond, almost as easy to use, and more economical to install. Made of heavy-gauge, UV-resistant rubber, liners come as big as 5,000 square feet, enough to construct an 18-inch-deep pond holding 42,000 gallons of water. They range in price from as little as $23 for a liner 5 feet square
to $4,500 for a 50- by 100-foot roll. 

A flexible liner needs to be held in place with some form of coping; fieldstones make a functional and beautiful addition. These can be cemented in place using any of the bagged mixes sold at building-supply stores. Remember that birds need to be able to reach the water to drink, so fill the pond right to the coping or stack some rocks on an underwater shelf as stepping-stones.

Water-garden-supply houses frequently promote electric pumps and filters as a means of keeping pond water clear, but a variety of submerged plants will do the job of filtering out sediment just as well, and they don’t add to your electric bill. On the other hand, a waterfall offers a wonderful place for birds to bathe.  From a wildlife standpoint, it’s desirable to leave a few inches of leaf litter
on the bottom into which amphibians can burrow during the winter. The only maintenance I perform on my water garden is topping off the water during summer months and removing excess leaves in fall and spring. The rest is pure pleasure. 
 
 
 
Sidebar

Lilypons Water Gardens
P.O. Box 10
Buckeystown, MD 21717
800-999-5459

Matterhorn Nursery
227 Summit Park Rd.
Spring Valley, NY 10977
914-354-5986

PERRY’S WATER GARDENS
1831 Leatherman Gap Rd.
Franklin, NC 28734
704-524-3264

Slocum Water Gardens
1101 Cypress Gardens Blvd.
Winter Haven, FL 33884
941-293-7151
(catalogue: $3)

Van Ness Water Gardens
2460 North Euclid Ave.
Upland, CA 91784
909-982-2425
(catalogue: $4)

Water Creations
2507 East 21st St.
Des Moines, IA 50317
800-475-2044

Waterford Gardens
74 East Allendale Rd.
Saddle River, NJ 07458
201-327-0721
(catalogue: $5)

Wicklein’s Water Gardens
1820 Cromwell Bridge Rd.
Baltimore, MD 21234
410-823-1335


 
 

© 2000  NASI

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