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Backyard WetlandWetlands filter excess pesticides and nutrients. Many plants and animals find a home in wetlands. In Your BackyardA mini-wetland in your yard can provide many of the same benefits that natural wetlands offer. A mini-wetland can replace the important natural functions of wetlands that may have been lost when your community was developed. A wetland in your backyard will temporarily store, filter, and clean runoff water from your roof and lawn. It will provide habitat for many interesting creatures--from butterflies and bees to salamanders, toads, frogs, and birds. Most wetland plants do not require standing water to grow successfully, and will survive even in an area that appears dry during most of the growing season. If you have a naturally occurring wet spot in your yard, or a low swale or drainageway with heavy clay soils, you easily can turn it into a wetland paradise. Even if you do not have a naturally wet spot, you can establish an area in your yard to grow many of the beautiful plants associated with wetlands. What Is a Wetland?A wetland is simply any area where water covers the soil or keeps it saturated for at least two or three weeks during the growing season. You will usually find them anywhere water accumulates at a rate faster than it drains away. Some are inundated year-round while others only hold water for brief periods in the spring. Most wetlands are covered with water for less than a month during the summer. Wetlands dominated by grasses, cattails, and similar herbaceous vegetation are referred to as marshes, while wooded wetlands, dominated by shrubs and trees, are called swamps. The saturation of the soil limits the types of plants you can grow to those with "wet feet." How long the soil is saturated determines which wetland plants will grow best. There are many small wetland plants that grow quickly when the soil is wet in the spring and disappear when the soil dries up. Species like cattails, bulrushes, jewelweed, and the attractive cardinal flower do well where there are alternating wet and dry periods. These plants will survive persistent flooding as long as most of the leaves are out of the water. Water lilies and pond weeds grow well in permanently flooded ponds. In your backyard, toads and tree frogs (spring peepers) will lay eggs and the pollywogs will mature where water only lasts 3 or 4 weeks; other frogs need longer periods. Where you have permanent water, the bullfrog pollywogs and small fish eliminate reproduction of most other frogs, toads, and salamanders. Mosquitoes will not survive in wetlands that dry out in less than a week after a summer rain or in wetlands connected to a deeper pond that supports small fish and large aquatic insects that feast on them. Where to Put a WetlandA natural depression or ditch that tends to stay wet is an ideal place to develop a wetland. Other areas with heavy clay soils that drain slowly may also be suitable. Better drained sites may require use of a plastic or other type of liner. Of course, if you are building a backyard pond, as discussed in another tip sheet in this series, a shallow area of saturated soil can be incorporated in the design. When selecting a site, consider:
Building a WetlandSince wetlands refer to a variety of conditions, there is a lot of potential for including wetland plants in your yard. You may want a wetland that only stays wet for a short period after heavy rains or one that stays wet most of the time. It depends on the site and your desires. Establishing a wetland in your yard may be as simple as planting wetland plants in an existing wet area, or it may require the same effort needed to install a backyard pond. Building a Wetland in an Existing Wet Area or DrainagewayIn some instances, all you need to do is stop mowing during dry periods. Too often homeowners go to great lengths to establish plants that are not adapted to the site or to modify the site, when it would be more effective to use plants suited to the conditions. Numerous landscape plants are well adapted to wet conditions and will provide beauty as well as wildlife habitat. Be sure to check the growth and rooting characteristics of trees you want to plant. Many wet soil tolerant trees have shallow root systems or brittle branches and must be planted a safe distance from buildings. Partially blocking a drainageway or small ditch to create your wetland by trapping storm water needs more planning. Where a low berm less than a foot high will create a small wetland, planning is not complicated if:
For sites requiring a higher berm, and those with a larger watershed, you need engineering advice. For sites with sandy soil or a lot of rocks, you also may need to install a plastic liner (described in the next section) under all or the lower portion of your wetland. To construct the wetland with a small berm to hold back water for a few days or weeks:
Building a Separate WetlandYou can create a wetland in any level area and make it suitable for most wetland plants by digging out a depression, lining it with plastic, refilling it with soil, and adding water. After selecting the site, you should:
Building a Wetland by a Backyard PondPutting a shallow wetland at one edge of your backyard pond will increase its value and attractiveness. If you are using a pre-formed liner for your pond, you may want to build the wetland as described above, with the water level slightly above the pond liner or the edge of the pond liner lowered a couple of inches to allow water to flow into the pond. This design filters sediment and other contaminants out of the water coming off your lawn or roof through the wetland before it enters the pond. The wetland area also protects fish and other aquatic life in the pond by removing any chlorine from city tap water you use. Establishing plantsThe plants you select for your wetland will depend on:
Select plants that are hardy for your area and provide the desired wildlife habitat and aesthetics. The species of plants most common in other wetlands in your area with similar flooding cycles will be easiest to grow and need the least maintenance. Choosing and Establishing Plants for PondsTo make part of your backyard like natural wetlands, use a mix of diverse plants. Most trees, shrubs, ferns, and many other plants grow best in soils that are only saturated early in the growing season and after heavy rains. Others, like the true bog plants, need almost continually saturated soil. Plants like water lilies need to be continually flooded. Once established, plants like cattails will thrive in water a couple feet deep, but also in areas that are wet for only short periods. However, most have a narrower tolerance range that may vary depending on where you live. Always check with your local nursery or other expert before making final decisions on what varieties to plant. Plants should always be purchased from a reliable source. Native Trees Tolerant of Wet Soils
Native Shrubs Tolerant of Wet Soils
Native Herbaceous and Flowering Plants for Sunny Moist or Boggy Conditions
Native Herbaceous and Flowering Plants for Shady Moist or Boggy Conditions
True Bog Plants Requiring Low pH and Sun
Numerous other native wetland species are available in most areas. There are also many species that have been naturalized in North America and are often considered native plants. Unfortunately, some of these species are more competitive and have become invasive, crowding out the native species that provide habitat for indigenous wildlife. SafetyLocate the backyard wetland where it is unlikely to attract unattended children. Check local safety ordinances and building ordinances for restrictions and permits. On the FarmIn the rural landscape, wetlands filter chemicals, excess nutrients, and sediment from flowing water, protecting streams and drinking water sources. They also provide habitat for many wildlife species. Across the country, many farmers voluntarily return formerly drained wetlands in crop fields and pasture to fully functioning wetlands. Many of these acres were marginally productive and returning them to wetlands provides significant ecological, economic, water purification, and recreational benefits. Many farmers enhance their wetlands with nesting structures for ducks and other birds, put in plants and annual seeding to provide winter food and cover for wildlife, and establish native wildflowers to make the landscape more attractive. More About Backyard Conservation |
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