Thursday, May 07, 2009

Success in a Soggy Garden

Many homeowners are frustrated by having low-lying areas in their yards which are always a bit on the soggy side. Fortunately, these wet areas can be turned into desirable landscapes which are beautiful, easy to maintain, and beneficial to the environment.

Using native or indigenous plants and a bit of creativity, you can transform mucky soils into lively gardens which can provide wildlife habitat, filter excess nutrients and pollutants from stormwater, recharge groundwater supplies, and control flooding. Natives are essential to this reclamation of wet areas. Over thousands of years, they have adapted to rainfall and seasonal temperature patterns; if you have a niche, they can and will fill it.

Before you start, you must consider whether your proposed garden’s location is near a building, public area, or pathway, where flooding might be a problem or where it might cause property damage. The goal is to take advantage of these wet areas, not to haphazardly create a pond or wetland, which requires extensive planning and effort.

Also, how will your wet garden fare during the summer? It is advisable to choose moisture-loving plants which can also tolerate semi-dry conditions. Most native plant lists and nurseries can suggest good possibilities. Perhaps you can divert some rainwater from your roof or patio toward this garden during dry spells. If so, slow the flow of that water by first directing it across a buffer strip of turfgrass to prevent potential wash-outs.

Next, develop a garden plan. An easy way to “design” the shape of your garden is to use a garden hose connected end-to-end. Move the hose around to match the outside contours of your soggy patch, or adjust the hose until you are pleased with a basic outline, whether oval, kidney shaped, or free-form.

What sort of garden will it be? If you are simply looking to fill a sunny area with trees and shrubs, look to large deciduous trees such as red maple, green ash, and white oak, or evergreens like the eastern red cedar or common juniper. In more closed quarters, you will find that many smaller trees and shrubs are commonly understory residents, and do well in a range from full sun to partial (and even full) shade, such as the ever showy shadbush, witch hazel, arrowwood viburnum, tasty elderberry, or redbud.

If your wet landscape is already under a shady canopy, select medium-sized specimens like river birch, spicebush, mountain laurel, or sweet pepperbush – usually a coastal plain plant, but a delightful magnet for butterflies and other wildlife.

Another approach is to underplant these or existing trees and shrubs with ferns and ground covers creating the illusion of a lush “forest floor.” Easily-established possibilities include Christmas, cinnamon, and sensitive ferns, although you might also want to tuck in – or substitute – clumps of wild ginger, wintergreen, and mountain stonecrop. These are all evergreen natives and a vast improvement over invasive English ivy. Plant them in natural-looking clumps of three-five per individual species.

Naturally, if your basic goal is merely to cover a muddy depression in your lawn, you can simply use these and other ground cover plants in groups by themselves.

Sunny wet zones allow you to plant for brilliant color and wildlife, especially nectar-feeding butterflies and hummingbirds, and other birds. Favorites include cardinal flower, great blue lobelia, wild columbine, foamflower, Virginia spiderwort, New York ironweed, wrinkleleaf goldenrod, Rudbeckia species like black-eyed-susan, New England aster, swamp milkweed, and Eupatorium species like Joe-pye-weed. These offer a tapestry of hues from red and yellow to pink and dark purple, and range in height from two or three feet to over seven feet; plant taller specimens toward the inside of your bed.

Regardless of sun or shade, you should always begin your project by applying a mulch layer several inches deep. Use a shredded hardwood mulch, which is less likely to wash or “float” away during a storm.

All of the species listed above are available through specialty nurseries, although local nurseries and garden centers are now featuring an expanding variety of natives. There are scores of other readily available plants suitable for your soggy garden.

Copyright 2009, Joseph M. Keyser

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