by Cindy Gilberg
A shady woodland garden is a favorite retreat during our hot and humid St. Louis summers. It is puzzling, therefore, why many gardeners scratch their heads and curse the shade. They say nothing grows there, yet a walk in Missouri’s woodlands reveals a diverse bounty of woodland plants. Begin by creating a strong backbone for the garden with some understory trees such as serviceberry, dogwood or redbud and large shrubs like wild hydrangea. Fill in with perennials and add the finishing touch—sweeps of ground cover species that offer a low maintenance solution and serve to visually define and unify the scene.
What exactly makes a plant a ground cover, since it is literally translated as a plant that covers that ground? A common interpretation is that they are low-growing plants that spread rather than remaining in clumps. However, masses of taller plants, both perennials and shrubs, function well as ground cover. Imagine large drifts of wild hydrangea and ostrich fern filling wide spaces amongst the trees and providing a textural backdrop to highlight shorter ground cover plants along the pathways. These shorter species include sedges, alum root, groundsel, and wild ginger, among others.
Ground cover plantings can be incredible problem solvers. Steep slopes are a classic example because not only is it dangerous to mow, erosion is often the real issue. Among some of most useful native plants in this group are sedges, beak grain grass, ferns, cliff and woodland goldenrod, fragrant sumac, wild hydrangea and woodland asters. Perhaps your property sits low and large areas remain wet. Sedges once again are effective as well as golden groundsel and most ferns. Another motive for choosing ground covers is to encompass groupings of trees to create an island bed. This protects exposed tree roots that often get cut by mower blades, is far more attractive than ‘tree donuts’ of mulch and offers an aesthetic break from lawn. A reduction in the amount of mowed lawn is another plus with savings of both time and fuel not spent mowing. Save lawn for areas where it is easier to grow and mow and for use as pathways around your property.
As you begin, here are a few tips to keep in mind. Never till under trees as this damages surface roots causing slow decline and death of trees. A layer of compost and soil, about 6” deep, can be spread over the surface under trees—don’t pack it around tree trunks. Shorter, shallow rooted plants such as wild ginger, woodland sedum and crested iris grow happily in this layer. Dig in and plant larger plants such as ferns, woodland goldenrod and shrubs, mixing some of the compost into the planting hole. Apply a 1-2” layer of compost annually, in late fall-early winter, to replenish the soil.
As with any garden design, pay particular attention to foliar texture and blend the plants together with contrast in mind. Short sedges and ferns offer a fine texture that blends well with the larger texture of wild ginger, groundsel and alum root.
Below is listed a sample of proven performers for use as native ground covers. This is by no means a complete list – try other native plants as you get to know them. These are readily available through most garden centers and GrowNative members.
Shorter ones = 12-15” tall
- Alum root Heuchera villosa or H. puberula
- Barren strawberry Waldesteinia fragarioides
- Crested iris (Iris cristata)
- Groundsel Senecio aureus (for moist soil)
- Groundsel Senecio obovatus (for dry soil)
Sedges
- Cedar sedge Carex eburnea
- Palm sedge Carex muskingumensis
- Pennsylvania sedge Carex pennsylvatica
- White tinged sedge Carex albicans
- Wild ginger Asarum canadense
- Cliff goldenrod Solidago drummondii
- Creek oat grass (Chasmanthium latifolium)
- Fragrant sumac Rhus aromatica
- Wild geranium Geranium maculatum
- Woodland goldenrod Solidago flexicaulis
Cindy Gilberg is a Missouri native and horticulturist whose work includes design and consulting, teaching and writing. Much of her work focuses on native plants, habitat gardens and rain gardens. Cindy’s projects include work at Shaw Nature Reserve and its Native Plant School, the Shaw Professional Landscape Series and the Deer Creek Watershed Alliance. You can contact Cindy at 314-630-1004 or cindy.gilberg@gmail.com.