Plants for very damp conditions #619370 - Ask Extension


Plants for very damp conditions #619370

Asked March 28, 2020, 1:49 PM EDT

I have a place in my yard that doesn't drain well. I am looking to plant some flowers that would attract pollinators and help to break up the clay soil. I know that over time I am going to have to build up the soil but I don't have the money to do that all at once now. What suggestions do you have? Currently the location has grass and gets morning sun but afternoon shade. It grows grass well but it is hard to maintain.

Montgomery County Maryland

Expert Response

If the site's poor drainage isn't posing a risk to structures - such as basement flooding - then working with what you have as-is would be the simplest, cheapest, and easiest long-term approach. Otherwise, building-up soil and changing grade can negatively impact and potentially smother existing plant roots, especially for trees.

Many choices exist for wet soil tolerant perennials and shrubs; native species might be best for pollinators, but any non-invasive species would suffice. The sources listed below are good places to start choosing native species tolerant of poor drainage and with wildlife value (where noted by the publications):

Starter ideas for native plants that tolerate afternoon shade (assuming no deer browsing issues) include:
  • Summersweet (Clethra alnifolia) - dwarf cultivars exist if wild types are too tall
  • Sweetspire (Itea virginica)
  • Chokeberry (Aronia arbutifolia and A. melanocarpa) - birds will eat the berries too; can sucker a bit; dwarf types of some exist here as well
  • Elderberry (Sambucus canadensis or S. nigra canadensis) - edible fruit (if cooked) that birds will also enjoy
  • Swamp Azalea (Rhododendron viscosum) - very fragrant and blooms much later than other azaleas
  • Buttonbush (Cephalanthus occidentalis) - best blooming in more sun, however
  • Lobelia (Lobelia cardinalis and L. siphilitica) - both good for hummingbirds, though the former is more short-lived and needs to be able to re-seed
  • White Turtlehead (Chelone glabra) - good for bees; our state butterfly uses this as a host plant, though it would be rare to see one in suburbia
  • Swamp Milkweed (Asclepias incarnata) - best blooming in more sun; host plant for Monarch butterfly
  • Marsh Marigold (Caltha palustris)
  • Blue Mistflower (Eupatorium coelestinum, now re-named Conoclinium coelestinum)
  • Blue Vervain (Verbena hastata) - of interest to smaller pollinators because the flowers are tiny
  • Lowbush Blueberry and Black Huckleberry (Vaccinium angustifolium and Gaylussacia baccata) - very similar in appearance and growth; birds enjoy the berries as much as we do; small bees and some small butterflies would visit the flowers
  • Virginia Bluebells (Mertensia virginica) - they will go dormant and disappear come summer, but return each spring
  • Monkeyflower (Mimulus ringens)
  • Beebalm (Monarda didyma) - also attractive to hummingbirds
  • Golden Ragwort (Senecio aureus, re-named Packera aurea) - early-blooming and good as a groundcover; can be a bit aggressive
  • Meadow-Rue (Thalictrum pubescens)

In general, a diversity of plants will serve pollinators best and attract the widest array of species. Many bees and butterflies forage in sunny sites, so including other sun-loving plants for pollinators elsewhere in the yard, if possible, may help draw them to the area. Central Maryland tends to have clay-based soils, and natives found in this habitat will not need soil improvements to grow well. Their growth over the years may help break up compacted soils, but in general, unless this area was destined for another use in the future this would not be needed.


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