Some gardeners improve wet, clay soils by adding copious amounts of sand and by building ingenious irrigation and raised bed systems. But others prefer to simply choose the plants best suited to soggy, boggy conditions. If clay soil and marshy situations dominate your region, your local state extension office can recommend ground covers, flowers, herbs, shrubs and trees which thrive not just in wet, clay soil, but in your specific climate as well.
Believe it or not, you can raise food on boggy soils. Among the perennial vegetables which thrive in wet, clay conditions are several plants we normally think of as purely decorative, but in fact have nutritious parts, such as the fiddleheads of ostrich fern or the petals and buds of the daylily. Other plants in this category include arrowhead, bamboo shoots, cattails, ground nuts, wild leeks, wild rice, water celery, water mimosa and watercress. Several fruiting plants also tolerate clay or boggy conditions, including cranberry, blueberry and elderberry bushes, bog myrtle and serviceberry trees.
Many ferns, hostas and grasses not only provide ornamentation in a boggy garden, but help prevent erosion and pollution through water runoff. All varieties of fern thrive in the wet, clay conditions of boggy areas: ostrich, cinnamon, maidenhair, and royal are just a few of the ferns which may be hardy in your area. Hostas often tolerate clay ditches and bogs, and multiply rapidly to cover large areas. They, like ferns, require shade to thrive. Good choices for ornamental and native grasses of varying heights include creeping bent grass, rushes, tufted hair grass, Indian grass, sweet flag, switch grass and fountain grass.
Shrubs and Trees
Along with the fruiting bushes and trees mentioned above, consider planting one or several willow trees to frame your landscape. All willow varieties, including weeping willows, grow incredibly fast and love boggy and clay conditions. River birches, honey locusts, sumac, aspens and cottonwoods also do well. Ad for shrubs, wild members of the holly family, including winterberry and inkberry, provide winter color and wildlife forage. Some gardeners have luck with cultivated hollies in their boggy area as well. Other shrub choices include laurel, rhododendron and azalea varieties.
Among the perennial and annual flowers which respond well to wet, clay soil are asters, daylilies, coneflowers, black-eyed Susans, Shasta daisies, Veronica speedwell , columbines, jack-in-the-pulpit and Joe-Pye Weed.
Among those bog- and clay-tolerant herbs which have culinary, cosmetic or medicinal use are mint, bee balm, coltsfoot and horsetail. Like some other bog-loving plants, these herbs spread rapidly, so place them only where they won't choke out more delicate species.