NATIVE SHRUBS FOR WET SITES
Dr. Leonard Perry, Extension Professor
University of Vermont
Generally a "native" plant is considered one already in an area when the first settlers arrived. Using such plants is becoming more popular, with several good shrub choices for wet sites.
These plants will tolerate soils near, but above the water table. They don't tolerate standing water, or their roots submerged in water, for long periods. Also, soils compacted, such as by construction or foot traffic, that do not drain well may be too restrictive for such plants to survive.
For a low groundcover, growing up to 1-1/2 feet high, Bog-rosemary (Andromeda polifolia) is a good evergreen choice. Very hardy, and slow growing, it needs moist and acidic soils. It has small, deep green leaves and urn-shaped, pinkish-white flowers in spring.
Bunchberry (Cornus canadensis), a deciduous (loses its leaves
in winter) groundcover, is more common, also quite hardy, and related to
the taller shrubby dogwoods. It forms a carpet-like mat, with attractive
white flowers and red fruit favored by wildlife. For moist acid soils
as well, this one prefers part shade.
A couple of low shrubs growing 1-1/2 to 3 feet high include Sweet Gale (Myrica gale) and Rhodora (Rhododendron canadense). Both are quite hardy, yet less commonly found. Sweet gale is upright with small blue-green leaves, and is good as a nesting area for birds. Rhodora is a deciduous azalea, with pinkish flowers before the leaves in spring. It is often found in bogs, which is a clue to the moist acidic soils it prefers.
For a small shrub 3 to 6 feet high, consider the Summersweet Clethra (Clethra alnifolia) or one of its several cultivars. Hardy to USDA zone 4, it is rounded in habit, with pink or white flowers in July or August, and yellow fall foliage. It prefers sun or part shade.
There are quite a few selections of medium shrubs growing 6 to 10 feet high. Three shrub dogwoods (Cornus) with rounded habits include the Silky (amomum), Redosier (sericea), and Gray (racemosa). With all hardy to USDA zone 4, the Redosier is hardier to zone 3 and has showy red twigs in winter.
All three dogwoods have white flowers and fruit in late summer which attract wildlife such as birds. The Silky Dogwood has bluish fruit, the Redosier has bluish-white fruit, and the Gray has white fruit on red stems. The Gray also has fragrant flowers, purplish fall foliage, and resists drought.
There are also three choices of deciduous hollies (Ilex) for
native, medium shrubs for wet sites. Hollies are different from most
shrubs, having female plants that bear the fruit, and male plants that
are needed nearby for pollination and fruit set on the female plants.
Inkberry (glabra) is hardy to USDA zone 5, has small evergreen leaves, and black fruit. It does not tolerate drought well. Winterberry (verticillata) is hardy to zone 3 with many, often less hardy, cultivars. This common deciduous shrub has bright red fruit in fall. Smooth Winterberry (laevigata) is hardy to zone 4, and is similar to Winterberry only less common, and with fewer and larger red fruit.
Choosing the right plant for the right site is the key to long term success and a sustainable landscape. More selections can be found in the publication "Landscape Plants for Vermont." This was revised and expanded in 2002 by Drs. Pellett and Starrett. It is available from the Vermont Master Gardener Program (www.uvm.edu/mastergardener/).