Thursday, December 6, 2007

Landscape - Landscaping Wet Areas

Wet areas on properties can be challenging to landscape as many common plant choices will not survive. Yet there are many plants that are well adapted to moist soils. The following is information on landscaping wet areas.

Wet areas in the landscape provide a great gardening opportunity. Swales between property lines or other low areas often stay wet for a while after a rain. There are many wonderful native plants that thrive in moisture; and wet soils discourage most invasive plants. Starting with the canopy layer, red maple (Acer rubrum), pawpaw (Asimina triloba), ironwood (Carpinus caroliniana), sweetgum (Liquidambar styraciflua), sweetbay magnolia (Magnolia virginiana), sourgum (Nyssa sylvatica), loblolly pine (Pinus taeda), sycamore (Platanus occidentalis), swamp white oak (Quercus bicolor), willow oak (Quercus phellos), and bald cypress (Taxodium distichum) are a few good choices.

Next add a shrub layer, which might include winterberry holly (Ilex verticillata), red chokeberry (Aronia arbutifolia), sweet pepperbush (Clethra alnifolia), button bush (Cephalanthus occidentalis) and smooth witherod viburnum (Viburnum nudum). There are very few woody plants that tolerate standing water. All these plants tolerate wet or moist soils, but if water pools on a routine basis, you may need to resort to herbaceous perennials only.

Some good perennials for moist sites include marsh mallow (Hibiscus moscheutos), blue vervain (Verbena hastata), cardinal flower (Lobelia cardinalis), great blue lobelia (Lobelia siphilitica), New York aster (Symphyotrichum novi-belgii), swamp milkweed (Asclepias incarnata) and Joe-pye weed (Eupatorium dubium or E. fistulosum).

This is only a small sample of perennials suitable for moist soils. With proper planning you can have a thriving garden that provides many seasons of interest. Sweetbay magnolia has early summer blooms combined with a lovely lemony fragrance; sweet pepperbush blooms in the summer (and has yellow fall color as a bonus); Joe-pye weed blooms in midsummer and marsh mallow, blue vervain and lobelia all bloom in late summer. In fall, you can count on purple foliage color from smooth witherod viburnum and red or orange leaves from red maple, sweet gum and sourgum trees. Finally, the red berries of winterberry holly provide color throughout the winter. Winterberry looks best when it is displayed against an evergreen background or in combination with a warm season grass, such as switchgrass (Panicum virgatum), to provide a tan winter backdrop.

Copied from "Liveable Plants for the Home Landscape", Authors: Susan Barton, University of Delaware, Sarah Deacle, Delaware Center for Horticulture, Gary Schwetz, Delaware Center for Horticulture, and Doug Tallamy, University of Delaware. For the full publication with photos go to http://ag.udel.edu/extension/horticulture/pdf/lowres18spreads.pdf

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