What to Plant When the Water’s Rising
Well, this winter’s polar vortex certainly tested plant hardiness. Now we’ve segued into the wettest May on record. With so many of us dealing with dense clay soils that don’t drain well anyway our trees, shrubs and perennials are STRESSED!!!!
Wet and squishy is one thing, but taken to the extreme end of the spectrum becomes “floodplain”. I define “floodplain” as standing surface water for 12-24 hours (or more) multiple days a year. I’ll skip the entertaining retail anecdotes where people share, “Well, the water does stand in that area for more than a day at a time, but it’s only a dozen or so times a year.” That’s when I counter that it’s a bit like saying you can only drown in a bathtub when there’s water in it. Smile face emoji? The point is it’s as important for roots to get oxygen as it is for our lungs.
Aside from rice, what Chicago area landscape plants survive floodplain conditions? Here are recommendations with a proven track record. The majority are native, or selections of native plants.
Trees:
(Quercus bicolor)
Majestic native with leaves like polished leather. Spreading canopy to 60’ tall, moderate growth rate.
(Betula nigra)
Glossy green leaves, clear yellow fall color and beautiful buckskin-colored peeling bark. Rapid growing to 30’, but dwarf varieties are available, too.
(Taxodium distichum)
Predictably broad conical silhouette with fernlike evergreen needles that surprisingly aren’t evergreen. Really rapid grower for those in a hurry. Dwarf and columnar varieties exist for your growing pleasure, too.
Shrubs:
(Aronia melanocarpa)
White flowers, striking green summer leaf, red fall color and large (yes) edible black fruit. Tolerates shade.
(Calycanthus floridus)
Selected, named varieties bear sweet, fruit-scented flowers late spring into summer. Performs in sun or shade, nice shiny foliage and clear yellow fall color.
(Cephalanthus occidentalis)
Long season of fragrant, white, sputnik-shaped flowers that later become red, persistent fruit. Glossy foliage. Ask for ‘Sugar Shack’, a compact variety that only gets 3-4’ tall. Tolerates shade.
(Cornus racemosa)
White flowers, white berries, burgundy fall color. Selections made for different heights. Does shade and wet well.
(Ilex verticillata)
Deciduous holly, females bear striking bright red berries in late summer lasting into fall until the robins devour them. Clear gold fall color even in partial shade. Must have a male plant (they come labelled as such) to pollinate the female. Both bear small white spring flowers. Sun to part shade.
Purple Osier Willow
(Salix purpurea ‘Nana’)
Naturally domed shrub with fine-textured silvery blue foliage on slender stems that move in the wind like an ornamental grass. Can get 6’ tall, 8’ wide. Really rapid grower in swampy sites, but can be pruned… frequently.
Perennials:
(esp. Cinnamon, Ostrich, Royal and Sensitive)
All will do in part/full shade. I particularly love Royal fern that will grow into magnificent 3’ tall clumps.
Hibiscus
(Hibiscus moscheutos)
Splashy, flashy (but too beautiful to be trashy) flowers throughout the summer in red, burgundy, pink or white. Sun is a must. Be patient, they’re typically late to come out of winter dormancy.
A number of different varieties with bold leaves, dazzling gold/orange flowers. Some morning sun, but keep them out of hot afternoon sun, or they’ll look wilted even when wet!
If you plant your floodplain with any of these hard-working, water-tolerant beauties landscape survival is assured!
Tony Fulmer
Chief Horticulture Officer