Many ornamental trees and shrubs thrive in Iowa's fertile, well-drained soils. Most trees and shrubs, however, don't like wet soils. Fortunately, there are plants that survive wet soils better than others. Trees and shrubs that tolerate wet sites include the following:
Freeman Maple (Acer freemanii). A group of hybrid maples arising from crosses between red and silver maples. They possess some of the best characteristics of each parent. The hybrids grow rapidly, have excellent fall color, and grow in most soils. Their mature height is 45 to 50 feet. Suggested varieties include 'Armstrong', 'Autumn Blaze', and 'Celebration'.
Serviceberries (Amelanchier spp.) are large, multi-stemmed shrubs or small trees. Several species and numerous varieties are available. Their mature height varies from 10 to 25 feet. Serviceberries are noted for their white flowers in the spring, edible fruit, and fall leaf color which varies from yellow to red. The ripened fruit (which resemble blueberries) can be eaten fresh, cooked in pies and other desserts or left for the birds.
River Birch (Betula nigra) tolerates heat and drought better than the white-barked birches. Also resistant to the bronze birch borer. The exfoliating bark varies from gray-brown to reddish brown. The variety 'Heritage' has a salmon-white bark. Often planted as a multi-stemmed specimen or "clump." The river birch grows 50 to 60 feet tall.
American Hornbeam (Carpinus caroliniana) is native to woodlands in eastern Iowa. It is noted for its very hard, tough wood. Also called ironwood. The small, shrubby tree grows slowly to a height of 20 to 30 feet. The American hornbeam does well in heavy shade and wet soils, but will tolerate sunnier and drier sites. In the fall, the foliage turns yellow to orange-red.
Green Ash (Fraxinus pennsylvanica) is a native Iowa tree. It grows well in both wet and dry soils. Its mature height is approximately 50 to 60 feet. The green ash is a fast-growing tree, but tends to break up in storms. Seedless varieties, such as 'Patmore', 'Bergeson', and 'Dakota Centennial' are preferred for home landscapes.
Sycamore (Platanus occidentalis) is one of the largest native Iowa trees. It can reach a height of 75 to 100 feet. Definitely not a tree for a small yard. Best suited for parks and other large open areas. Has interesting exfoliating bark. Anthracnose (a fungal disease) is a problem in cool, wet springs. Symptoms of anthracnose include heavy leaf drop.
Swamp White Oak (Quercus bicolor) is a large-growing oak which may eventually attain a height and spread of 60 feet. While difficult to locate in nurseries, it is sturdy and adaptable.
Pin Oak (Quercus palustris) is widely planted because of its pyramidal habit and ease of transplanting. Unfortunately, iron chlorosis is a serious problem in alkaline soils. Chlorotic foliage is a sickly yellow-green. The pin oak is not a good street tree because of the drooping lower branches. Fall leaf color varies from bronze to red. It grows 60 to 70 feet tall.
Bald Cypress (Taxodium distichum) is a deciduous conifer. Native to swamps in the southeastern United States, it does surprisingly well in the north. It does best in the southern half of Iowa. The foliage is an attractive yellow-green in the spring and turns to russet in the fall. The bald cypress has a pyramidal growth habit and may eventually reach a height of 50 feet.
Red Chokeberry (Aronia arbutifolia) is an upright, suckering multi-stemmed shrub that grows 6 to 8 feet tall. Noted for its red fruit in late summer and fall. Leaves turn a reddish purple in fall. The variety 'Brilliantissima' produces the best fall color (scarlet) and a large crop of glossy red fruit.
Buttonbush (Cephalanthus occidentalis) is native to swamps and other wet areas. The shrub has glossy green foliage and creamy- white flowers in globular heads in August. Mature height is about 6 feet, though it can grow up to 12 to 15 feet in southern areas of the United States.
Redosier Dogwood (Cornus sericea) is a native Iowa shrub that grows about 6 to 8 feet tall. Its bright red twigs are attractive in winter. Several varieties are available. 'Isanti' and 'Kelseyi' are compact, red-stemmed shrubs. 'Flaviramea' has yellow stems.
Common Winterberry (Ilex verticillata) is a deciduous holly. The deep green leaves drop off in the fall revealing bright red fruit. The shrub attains a height of 6 to 10 feet. Hollies are dioecious; male and female plants are required for fruit set. The varieties 'Sparkleberry', 'Winter Red', and 'X-mas Cheer' produce abundant bright red berries. Winterberry requires an acid soil.
Purpleosier Willow (Salix purpurea) is an 8 to 10 foot tall shrub. 'Nana' is a compact form which grows only 4 to 5 feet tall. 'Streamco' is a Soil Conservation Service, USDA introduction which was developed to prevent soil erosion along stream banks. The purpleosier willow is only one of many willows that grow well in wet soils.
American Elder (Sambucus canadensis) is a native suckering shrub that produces large clusters of purple-black fruit in late summer. The ripened fruit are good for jellies, preserves and wines. The fruit are also attractive to birds. Its mature height is 6 to 10 feet.
When selecting trees and shrubs for the home landscape, gardeners should select plants suitable for the site. Wet soils require plants that are adapted to these sites.
This article originally appeared in the June 23, 1993 issue, pp. 1993 issue, pp. 99-100.