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Naturalizing Native Plants under Trees Summer and fall bloomers round out the season. They include purple coneflower (Echinacea purpurea), star coreopsis (Coreopsis pubescens), downy skullcap (Scutellaria incana), showy goldenrod (Solidago speciosa), Ohio horsemint (Blephilia ciliata), sweet coneflower (Rudbeckia subtomentosa), American bellflower (Cam-
or March by killing an area of turf grass about 200 square feet (10 x 20). If you are ambitious, double or triple this amount. This can be done by pinning down a tarp or a piece of plastic for 8 to 10 weeks in the shade of medium (40+ feet) to large trees (60+ feet), possibly circling the trunk of one. Then remove the covering, install your plants, lay 2
ample, if your planting area is 200 square feet, and you are planting 18 inches apart, then you will need 103 plants total. At 20 inches apart, you will need 83 plants. If you are planting on a budget, consider buying plugs or small pots and plant 24 inches apart (58 plants). The next year in April, look for new seedlings that will begin to ap-
Photos by Scott Woodbury.
f you are struggling to grow lawn under the shade of trees, then maybe it’s time to unleash a patch of woodland wildflowers. Virginia bluebell (Mertensia virginica), wood poppy (Stylophorum diphyllum), Jacob’s ladder (Polemonium reptans), wild geranium (Geranium maculatum), woolen britches (Hydrophyllum appen-
Jacob’s ladder, wild sweet William, blue-eyed Mary, Virginia Bluebell, and Wood Poppy
Wood poppy and Ostrich fern
diculatum), yellow violet (Viola pennsylvanica), wild sweet William (Phlox divaricata), roundleaf groundsel (Packera obovata), and columbine (Aquilegia canadensis) are all spring-blooming species that work well naturalized beneath the high branches of oak, sweet gum, or black walnut trees. Because many spring wildflowers go dormant by summer, mix in sensitive fern (Onoclea sensibilis), Maidenhair fern (Adiantum pedatum), or Ostrich fern (Matteuccia struthiopteris) to fill in gaps that appear mid-season and provide structure. Shrubs, including smooth hydrangea (Hydrangea arborescens), beautyberry (Callicarpa americana), and shrubby St. John’s Wort (Hypericum prolificum) are all shade tolerant and help provide year-round structure.
inches of ground leaf mulch on the bare soil, and water immediately. (Avoid cutting medium to large tree roots while planting large container plants.) If it doesn’t rain, water weekly and finally, keep the weeds out. Remove lower tree branches to a height of 15 feet for medium trees and 25 feet for large trees to allow indirect side-light to enter the garden. I like to install plants 18 to 20 inches apart. This way, plants grow in thickly by the following season and work to crowd out some of the weeds. To calculate the number of plants needed, there is a helpful plant calculator at classygroundcovers.com. Plant in a triangular pattern. For ex-
panula Americana) and eastern blazingstar (Liatris scariosa). Don’t forget grasses and sedges. I recommend starting with a few woodland rye (Elymus virginicus), bottlebrush grass (Elymus hystrix), American beakgrain (Diarrhena obovata) or river oats (Chasmanthium latifolium). Sedges like palm (Carex muskingumensis), oak (C. albicans), star (C. radiata), Pennsylvania (C. pennsylvanica), and cattail (C. typhina) add a fine-textured contrast to the wildflowers. Remember that in nature, grasses and flowers are randomly mixed like a tossed salad. This approach will look terrific beneath the trees in your yard as well. Start your project in February
SCOTT WOODBURY Horticulturist 16
March 2021 | kcgmag.com
pear and spread. You may expand the planting area outward to make it bigger or dig up and move seedlings to create new beds. This is what I mean by unleashing woodland wildflowers. They will spread by themselves, especially if you rake up tree leaves in February or March so that new seedlings can germinate in April and grow in the bare spaces, unencumbered by a thick layer of leaves. In February or March, trim spent foliage and stems to a height of 8 to 22 inches. Many species of native bees nest in dead stems. New plant growth in April will hide the stubble. What are you waiting for? It’s time to unleash woodland wildflowers in a shaded space near you. What could be more fun and beneficial to human and wildlife health? Happy gardening!
Horticulturist Scott Woodbury is the Curator of the Whitmire Wildflower Garden at Shaw Nature Reserve in Gray Summit, MO, where he has worked with native plant propagation, design, and education for 30 years. He also is an advisor to the Missouri Prairie Foundation’s Grow Native! program. Find suppliers of wildflowers for shade and other native plant resources at www.grownative.org, Resource Guide.
