It is not necessary to dig a hole to properly plant most of the prairie plants. It is possible to use a spade, shovel, or tree planting bar to make a narrow, deep hole in the soil. Do this by pushing your planting tool into the soil and then rocking or pulling it back and forth to widen the hole. The root system of the prairie plants can then be placed into this hole, making sure that the root crown is about one inch below the soil level. This is very important because root crowns that are exposed will be killed by the winter temperatures or they will fail to grow properly. Also be sure to place all of the roots into the hole before closing it firmly with your foot. If the hole is not closed firmly around the roots, they will dry out and the plant will die.
When the planting is underway, it is best to avoid planting the rootstocks of the mesic species in areas where water stands for long amounts of time. Saturated soil will cause the rootstocks of compass plant, prairie dock, blazing stars and rattlesnake master to rot, resulting in the loss of the plant.
The planting designed for your back yard will be viewed from up close, not from a distance. For this reason, spacing is a very important part of the prairie planting. Native prairie remnants are viewed with emphasis on the entire site, not so much on individual plants or a particular group of plants in the prairie. Your backyard planting will be viewed with emphasis placed on individual plants or a group of plants, not the planting in its entirety. Most prairie plants are clump forming species that should be planted about 18 to 24 inches apart. These plants will mature and grow larger with time. Placing the plants closer together will detract from the planting because the features of individual plants will blend and become masked and less noticeable to the visitor to the prairie garden. This is a situation that should be avoided.
In order to create a dry prairie planting, it will often be necessary to bring sand and gravel to the prairie garden site. The gravel should be from non sedimentary rock whose individual pieces are about one inch in diameter. A layer of this gravel, approximately twelve inches thick, should be placed on the prairie garden site to facilitate the rapid drainage that is characteristic of many dry prairies. A layer of non-washed sand, varying in thickness from 12 to 36 inches, should be placed on top of the gravel and shaped to create small knolls and depressions. An area of bare sand could also be left unplanted to simulate a blowout and help create the barren appearance of the dry prairie. Once this is done, it may be necessary to place railroad ties or landscape timbers around the planting to hold the sand in place until the prairie plants have established their root systems.
Due to the great variety of dry prairie types in Illinois, the dry prairie landscape plan has the potential to include many colorful and unusual plant species. Most plants of these prairies are the short to mid height species from the hill and sand prairies as well as prairies found on dolomite in northwestern Illinois. The primary grass in these prairies is little bluestem, and it should be the grass of choice in the dry prairie garden. This grass has superior fall color, and a silver form of this plant exists that will greatly enhance the beauty of the planting throughout the growing season. Other grasses that can be included in the dry prairie planting are side oats grama, hairy grama, reed grass, June grass, and needle grass. Both hairy grama and side oats grama are small plants that should be placed at the front of the planting where they can be easily seen (Appendix 4).
A wide variety of wildflowers or forbs can be included in the dry prairie planting, including cactus, goats rue, prairie clovers, goldenrods, and asters. If cacti like the eastern or plains prickly pear are included in the planting, include a sprawling or decumbent form as well as a form that is erect with long, deflexed spines. Erect forms of the cacti add greatly to the appearance of the planting. Dry prairies, particularly sand prairies, have several short height plants that have very colorful flowers, including cleft phlox, lance-leaved coreopsis, and birds foot violet.
When planting the dry prairie plants, it is important to give individual plants enough space so the entire aspect of the plant can be seen. This is especially true of sand milkweed, goat's rue, hairy grama grass, prickly pear cactus. Dry prairies are usually not as dense as other prairie types, and you should try to duplicate this feature in your planting. The dry prairie planting design (Figure 7) incorporates some of the more common dry sand prairie species. Substitutions can be made in the plants that are listed if other suitable plants are not available. Be sure to keep small plants to the front so they are not obscured by larger plants.
Mesic, tallgrass prairie was the most common prairie type in Illinois prior to cultivation in the 1800's. The location for a planting of this type should be very sunny and characterized by a rich, black soil free from limestone gravel, oil or tar, or other materials which would diminish the growth of plants and overall success of the planting (Figure 8).
Included in the list of plants for this prairie type are the big prairie grasses, big bluestem and Indian grass, that form the matrix of this prairie. A wide variety of wildflowers are available for this type of planting, including rattlesnake master, prairie dock, compass plant, Culver's root, alum root, and several species of blazing star. Due to the great variety of wildflowers, it is possible to select some very vivid colors, like the orange of prairie lily, the white of Culver's root, and the deep purple of the prairie gentian.
The tall prairie grasses, including big bluestem, Indian grass, and gama grass, all display outstanding fall color. However, one of the most desirable native grasses for landscaping, northern prairie dropseed, does not have much fall color. It does have a beautiful growth form resembling a water fountain when mature, and aromatic seeds. Some of the shrubs of the mesic prairie, namely hazelnut, winged and smooth sumac, and prairie willow, all have attractive stems, and hazelnut and the sumacs have excellent fall color (Appendix 5).
There are also a number of plants that are excellent for attracting butterflies in the mesic prairie planting. These include the blazing stars, Culver's root, wild quinine, and rattlesnake master. If your planting contains these plants, your site will be a favorite place for butterflies, bees, and other insects when these flowers are in bloom.
As with the dry prairie planting, it is best to keep the plants far enough apart that they retain their individual shapes and do not become entwined with adjacent plants. You may also find that some plants, in the absence of competition, will grow tall and lanky, requiring staking.
This is a prairie type best placed along the edges of an existing pond or stream (Figure 8). Most backyard plantings can not be accomplished without the excavation of soil to create the depression necessary to hold water to permit the growth of wet prairie species. Such planting sites will add diversity and beauty to the back yard and create habitat for birds and other animals that utilize the community types.
The predominant grass of this prairie type is cord or slough grass, a tall grass with sharp leaf margins, that spreads mostly by rhizomes. The long, pendulous leaves of this grass turn a lemon yellow color in the fall. Another plant of the wet prairies, wild blue iris, will add significantly to the site when in flower in June. Red osier dogwood, with its red stems, and indigo bush, with its purple flowers and orange stamens, will add greatly to the prairie planting. These should be placed at a slightly higher elevation because they will be less tolerant of standing water.
Two of the most colorful wildflowers in the wet prairie planting will be the great blue lobelia and the cardinal flower. These two plants are very spectacular when in bloom. Swamp milkweed will attract a large number of insects, including butterflies and bees.