Homeowners' landscapes vary greatly in amounts of sun exposure, soil type and soil moisture. In some cases, one yard's landscape characteristics may vary greatly from those of an adjacent yard or even differ throughout a yard. Although at first wet areas may seem unfitting for plants, several species and cultivars thrive in moisture.
Moist Soil and Wet Soil Descriptions
Different levels of wetness occur in soil. The term moist soil, or mesic soil, refers to soil that keeps its moisture at all times, especially in its top few inches, but it isn't soggy, and water doesn't stand on it. Wet soil, or hydric soil, on the other hand, either has in a small amount of standing water constantly or most of the time, or has a soggy texture at all times. Many of the plants that do well in wet soil are adaptable to moist soil, some are even drought-tolerant, allowing you some freedom when choosing plants.
If you have a marshy area in your landscape that always -- or almost always -- has standing water, don't fret. Several U.S. native plants thrive in that condition and can add color and texture to an otherwise unusable spot.
If a large tree is what you're after, then consider a bald cypress (Taxodium distichum), which is hardy in U.S. Department of Agriculture plant hardiness zones 5 through 10. This native grows naturally in swamps, floodplains and similar areas throughout much of the eastern United States. It has an unusual characteristic: It is a deciduous conifer -- a needle-bearing plant that loses its needles in fall or winter. The tree's large size -- more than 130 feet in the wild but rarely that tall in residential landscapes -- makes it unsuitable for small yards.
River birch (Betula nigra), hardy in USDA zones 4 through 9, features papery bark and is another native option for wet areas. It most commonly grows as a multi-trunk tree reaching 40 to 70 feet in the landscape, but it can grow as a single-trunk tree when trained to do so from a young age.
The native Virginia sweetspire (Itea virginica), which is hardy in USDA zones 5 through 9, is among the most adaptable plant nursery staples. This 3- to 5-foot-tall, deciduous shrub can handle full-sun to mostly shady locations and grows in a wide range of soils. In the wild, it often grows in swamps and low, wet, wooded areas. A profusion of cylindrical and drooping racemes of white, fragrant flowers covers the shrub in early summer.
Another native swamp-dweller is buttonbush (Cephalanthus occidentalis), hardy in USDA zones 5 through 10. This woody, deciduous shrub can reach 20 feet tall in the wild but typically grows to a height of 6 to 8 feet in residential landscapes. In late spring and summer, the shrub produces 1-inch-diameter spheres covered in tiny white flowers. Like sweetspire's blooms, buttonbush's flowers are fragrant.
Blue flag iris (Iris versicolor) is another native plant that thrives in standing water -- up to 2 to 4 inches. It is hardy in USDA zones 3 through 9. This herbaceous perennial's violet-blue flowers come up in late spring and early summer amid long, swordlike leaves that reach 2 1/2 feet tall.
If you want a specimen plant for a boggy area, then consider the native swamp rose mallow (Hibiscus moscheutos), a herbaceous perennial that is hardy in USDA zones 5 through 10. Some of its varieties reach 7 feet tall, and all of them have large flowers -- some of them dinner-plate size.