A favorite destination for gardeners and nature lovers alike is the woods. The Chicago Botanic Garden's McDonald Woods was once a part of a large oak woodland community. Over the course of many years and much development, this woodland became fragmented from the natural habitats that surrounded it. Fortunately, through careful management, the Garden is restoring this beautiful woodland. Gardeners often wonder if it's possible, in suburban or even urban areas, to establish a little piece of woodland of their own.
Jim Steffen, ecologist at the Chicago Botanic Garden, says yes, it is possible, but your focus must be less on individual plants and more on the whole plant community. He offers the following guidelines for gardeners interested in establishing — and then managing — a woodland community of plants:
Woody plants are not all that necessary for a woodland garden, but they will provide shade, protection, and some leaf litter. They will also provide food and habitat for other animals and insects that make up the entire woodland community. If you don't have trees, you can use the side of a building to create needed light shade. The north or east side of a house or garage is best for understory woodland plants since they require only 15 to 20 percent full sun per day to flower and maintain themselves.
The less you do to change the existing soil, the better. There are woodland species of plants that meet every soil and moisture condition. Know your plants and their cultural needs! Some woodland plants can grow in wet clay; some thrive in dry woodland situations. There are even intermediate plants for the in-between zones.
Disturb the soil as little as possible. Don't mulch your plants. Don't fertilize. Tilling the soil will release nutrients and expose weed seeds. If you elevate the nutrient level, weeds will respond mightily. The native plants you plant are not used to excessive nutrients. In their natural habitat, they are used to competing hard for little. Don't start off with a cycle of overfeeding. Soil nutrients in a woodland are locked up in the root systems of its plants. The woodland soil is really only a few inches deep and generally on the acid side. If the soil is too rich, many plants will put out leggy but weak growth.
Water only to get plants established. Native plants are used to competing in stressful situations. Encourage the plants in your garden to be low-maintenance.
Plant lots of diverse plant material. This ensures survival of the community if disease or insects attack, since pests target individual species, not an entire community of different species. Pack the native plants in closely. If you leave too much space between plants, the seeds from just one or two plants will germinate and take over. Open space also encourages weeds.
Plant the entire community of plants together at the same time. It will be easier to get the many species growing together. The healthy competition and relationships among plants are part of their genetic memory. Spreading plants are more likely to stay in place when they are planted as part of their whole native community. Adding plants later is difficult because competition may be too great for new plants to establish easily.
Every other year, remove the fallen leaves. This allows germination of species whose seeds require light to germinate or are inhibited by other properties of leaf litter.
Regular mowing or clipping of all vegetation (or controlled burning where allowed) helps control the invasive plants like garlic mustard or buckthorn.
Avoid collecting plants in the wild since that disrupts the fragile balance of plant relationships within that entire community. Collecting in the wild also depletes the supply of native plants and leads to degradation of their natural habitat. Ferns and spring ephemerals are often wild-collected. Scatter seeds from your existing plants to encourage self-seeding. Try to grow plants from seed (many ephemerals require five to seven years to flower from seed) or buy plants from nurseries that have propagated their own plants (see list below). Consider recognized seed exchanges or rescue organizations like "The Wild Ones" as plant sources.
Jim Steffen recommends the following plants to establish a woodland garden. He has included many summer woodland plants that will take over as the spring ephemerals fade. These plants are suited to open shade conditions.
Bloodroot, false rue anemone, wood anemone, toothwort, rue anemone, spring beauty, Dutchman's breeches, white trout lily, Virginia bluebells, twinleaf, large-flowered trillium, early meadow rue, bellwort, wood betony, purple spring cress
Nannyberry, downy arrowwood, American hazelnut, serviceberry, wild plum, wild black currant, New Jersey tea, white oak
Woodland phlox, Jacob's ladder, wild columbine, wild hyacinth, prairie alumroot, many species of sedge, blue eye grass, fire pink, purple meadow rue, white wild indigo, smooth beard tongue, tall anemone, purple milkweed, butterfly weed, silky wild rye, black-eyed Susan, self heal, starry campion, bottlebrush grass, New England aster, tall bellflower, tall coreopsis, wild rye, great blue lobelia, Short's aster, sneezeweed, cardinal flower, smooth blue aster, white or red baneberry, Jack-in-the-pulpit, wild geranium, shooting star, large-leaved aster, purple giant hyssop, elm-leaved goldenrod, false dandelion, yellow pimpernel
Recommended Nurseries for Not Wild-Collected Plants
• Natural Gardens, St. Charles, Illinois
• Country Road Greenhouses, Rochelle, Illinois
• Prairie Moon Nursery, Winona, Minnesota (has Illinois ecotypes that you can request)
• Genesis Nursery, Tampico, Illinois
• Ion Exchange, Harper's Ferry, Iowa
• J.F. New and Associates, Walkerton, Indiana
• Prairie Restoration, Princeton, Minnesota
• Prairie Ridge, Mt. Horeb, Wisconsin
• Prairie Seed Source, Northlake, Wisconsin
• Possibility Place, Monee, Illinois