If a section of your landscape is poorly drained, there are a number of trees and shrubs that will adapt over time to short periods of wet or soggy soils. Plant roots must survive in low oxygen soils. Your choices of plants are not lengthy; few landscape plants will not tolerate root suffocation for even brief intervals of time.
On landscaping sites with poor drainage, start with trees and shrubs that native to wet bottomland areas. They make the best candidates. When planting tolerant trees and shrub species, plants must have a period of time to adapt to the flooded, low oxygen soils. They are likely shallow-rooted and require staking for initial support. Over time, plants will develop physiological and anatomical features to tolerate poor drainage. For example, bald cypress (Taxodium distichum) develops “knees” on the ground surface to capture air.
Plant scientists at North Carolina State University in Raleigh, NC recommend starting with small plants that have been grown on poorly drained sites. It also helps to create raised beds, swales, grassed waterways, and drainage lines that can divert excess water away from planting sites. The following list is not complete, but does include some great plants. Many are excellent choices for inclusion in rain garden sites.
Tree List:
Red Maple (Acer rubrum)
Silver maple (Acer saccharinum)
Pawpaw (Asimina triloba)
River birch (Betula nigra)
Hackberry (Celtis occidentalis)
Green ash (Fraxinus pensylvanica)
Eastern redcedar (Juniperus virginana)
Sweetgum (Liquidambar styraciflua)
Sweetbay magnolia (Magnolia virginiana)
Blackgum, tupelo (Nyssa sylvatica)
Swamp white oak (Quercus bicolor)
Bur Oak (Quercus macrocarpa)
Willow oak (Quercus phellos)
London plantree (Platanus x acerfolia)
Willows (Salix spp.) -tree and shrub forms
Bald cypress (Taxodium distichum)
Eastern arborvitae (Thuja occidentalis)
American Linden (Tilia americana)
Canadian hemlock (Tsuga canadensis)
American elm (Ulmus americana)
Shrub List:
Summersweet, sweet pepper bush (Clethra alnifolia)
Buttonbush (Cephalanthus occidentalis)
Red osier dogwood (Cornus sericea)
Common witchhazel (Hamamelis virginiana)
Possumhaw (Ilex decidua)
Winterberry holly (Ilex verticillata)
Yaupon holly (Ilex vomitoria)
Virginia sweetspire (Itea virginica)
Ninebark (Physocarpus opulifolius)
Dappled willow (Salix integra ‘Hakuro Nishiki’)
American elderberry (Sambucus canadensis)
Snowberry (Symphoricarpos alba)
Coralberry (Symphoricarpos orbiculatus)
Arrowwood (Viburnum dentatum)
Nannyberry (Viburnum lentago)