Establishing and maintaining a prairie garden
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Over the last 150 years more than 99% of the midwestern tallgrass prairies were converted to homesteads, agricultural fields, cities, and highways. In recent years, however, interest in prairies has soared, since people realized the beauty of native grasses and wildflowers. Much of the charm and appeal of prairies comes from wildflowers, such as coneflowers, prairie phlox, false indigo, and orchids. The great beauty of prairie wildflowers and grasses has prompted many people to create prairie gardens in their landscapes. People find prairie gardens attractive, as do many types of birds, butterflies, and other native wildlife. Over the years, prairie gardens may take less time and expense to maintain than conventional lawns, since they reduce the use of pesticides, fertilizers, and mowing.
Even though prairies aren't native to all regions, they can be created in most areas. Prairie management includes removal of weeds and volunteer woody plants that compete with prairie plants for water, light, and space.
What is a prairie?
Prairies were once the dominant vegetation from Ontario south to Texas, and from Colorado and Montana east to Indiana. Prairies are classified as tallgrass, mixed grass, or shortgrass depending on yearly rainfall. In Minnesota, tallgrass prairies occurred in the south and west, while coniferous forests covered most of the north and northeast. The two regions were separated by a transition zone, called the oak savanna, which consisted of prairie plants with oak and elm trees. Prairies are ecosystems areas that receive limited rainfall and usually have hot summers and cold winters. Prairies are dominated by grasses and maintained by periodic fires. Prairie soils are typically deep and rich in organic matter from the decomposition of plant material, especially the fibrous roots of grasses produced in previous growing seasons. The tallgrass prairies of Minnesota and Iowa were once the homes for mammals such as the bison and red-backed vole, birds like the greater prairie chicken and the upland sandpiper), as well as unique insects, including the powesheik and ottoe skipper butterflies. The short and mixed grass prairies of the Dakotas and Nebraska contained prairie dogs, pronghorn antelopes, and black-footed ferrets. As the prairies disappeared, so did many of these animals.
Planting a prairie garden
1. Site selection
Prairie plants grow best in full sun and in open spaces. When selecting a site, look for areas with the maximum sun exposure with minimal root competition from trees. Ash, basswood, and maple trees provide more competition for prairie plants because they have many surface roots which compete for water and nutrients. Prairie plants often are more compatible with bur or white oak.
Knowing your soil type and surface drainage is quite important when selecting plants for your prairie. Native prairie soils vary greatly in composition, from dry, gravelly, sandy soils which hold little moisture to silty or heavy clay soils that can hold excessive water. Standing water on a site or water that does not drain from a 1' deep hole within 24 hours are indicators of wet and poorly drained soils. Knowing the soil drainage of your site is really more critical than taking a soil test which is typically done in planting a garden. Although you may have a soil test done, (soil test information is available from your county extension agent or from the University of Minnesota soil testing labs*) it is not critical in establishing a successful prairie garden. Understanding the drainage and sun/shade exposure of your site is essential for selecting plants that thrive in your location.
Determine if there are weed ordinances in your city. These ordinances were originally designed to keep yards more attractive and to control the spread of noxious weeds by keeping lawns cut to a certain height. Ordinances vary from one city to another, so call your city government to find out the specifics on the weed ordinances in your community. Consider using some "elements of care" such as mowed edges, signs, bird houses, edging fences, etc., near your prairie to show the area is meant to be there.
Also, prairies can be fire hazards during dry weather. Leave at least 20 feet of conventional lawn or noncombustible surface between the prairie and buildings or any other combustible items.
2. Site preparation
The first step in preparing the site for a prairie garden is removing all existing vegetation. If you try to scatter seeds or put young plants into existing vegetation, you will have a very low likelihood of success. Maximize your success by reducing the existing plant competition.
There are three commonly used procedures to establish a prairie in an existing lawn or area of other vegetation. The first method is to put a dark plastic sheet, tarp, or pieces of plywood over the grass for at least two months before you begin planting. This kills the grass, making it much easier to remove, although tough perennial weeds, such as thistles and quackgrass can survive. Once the vegetation is dead, till the area thoroughly. This method often works best when begun in the summer or fall to prepare for a spring planting.
The second procedure is to turn the soil and cultivate the area every few weeks for a complete growing season. Turning the soil brings weed seeds to the surface, and cultivating kills the seeds that have germinated since the soil was last turned. Over time, many of the weed seeds present in the soil will germinate and die. If possible, till to a depth of 12" or more and rake the area to create a uniform fine seedbed.
A third method, and probably the most common method of establishment, involves using a nonselective herbicide containing the active ingredient glyphosate, such as Round Up® or Kleenup®, to kill all existing vegetation. As with all herbicides, be sure to read and follow all label directions. When the vegetation has died in about two weeks, till to a depth of 12" or more. If a slit seeder will be used, tilling may be eliminated and the now dead vegetation can be mowed to a 1"- 2" stubble. This dead mat of roots and sod may actually act as a mulch and prevent excessive weed growth.
3. Plant selection
Always select plants with the characteristics of your particular site in mind, because plants vary in their tolerance of light and moisture. Include grasses because they provide physical support, weed competition, protection for wildflowers, and a source of food and shelter for birds during the winter. Prairies typically consist of 60% - 80% grasses. A brief list of common prairie plants can be found in Table 1, For a more complete list see Minnesota Extension Service publication Plants in Prairie Communities (FO-3238).
4. Seeds vs. plants
You can start a prairie from seeds or plants; each has its own benefits. Starting from seed is more economical, but it will take two to five years for the plants to reach full size. Plants are more expensive, but establish quickly and may flower the first year. Also, some species are available only as live plants. You can control placement of plants, and they can easily be planted anytime from spring through fall. "Prairie-in-a-can" mixes are available from a wide variety of sources, but often contain marginally hardy perennial and annual species that don't return in subsequent years. Better results may be achieved by using seed mixes created for your area by local seed dealers. Be sure that any seeds you purchase are packaged for the year that you will sow them.
5. Planting dates
The best time to direct sow seeds outdoors is after frost and before the heat of summer. For example, in central Minnesota this is between May 20th and June 20th, although seeds can be sown as soon as the soil can be worked. Dormant seeding in the fall, between mid-October and freezing, is another option.
Even seed distribution and good seed-to-soil contact are vital for successful seed germination. Broadcast seed by hand or use a spreader. For small seeds, mix with a bulking agent such as clean sand or dry sawdust for a more uniform seeding. Seed slowly and make passes from two different directions to cover the area completely. Flower seed can be concentrated in high-priority areas or spread evenly throughout the site. Many seeds are very small and should be spread thinly to achieve the best results. Seeding rates vary due to seed size and germination. As a general rule, use 1/2 lb. of grass seed per 1000 square feet, and 2 ounces of wildflower seed per 1000 square feet. ore specific instructions on seeding rates can be obtained from the information provided when purchasing seeds.
Watering after seeding improves germination, but is not essential. Covering with a thin mulch of clean, weed-free straw prevents drying out, reduces exposure to wind and animals, and is important in preventing erosion on slopes. Grouping several plants of the same species together can make a showy display and can increase pollination and seed set.
Contact the University of Minnesota soil testing labs by phone at 612-625-3101, or by mail at 1529 Gortner Avenue, St. Paul, MN 55108.
Your biggest task in the first few years of a prairie planting is weed control. Weeding, burning, and mowing are the most effective ways to control weeds.
In small areas, removing and cutting back weeds are the most efficient methods. The most challenging aspect of these tasks is distinguishing between prairie plants and weeds. If you aren't sure what a seedling is, wait a week and look again, but be sure to remove the suspected weeds before they flower and set seed.
The best way to manage a large prairie is through the use of controlled burns. Fire promotes plant growth by keeping down competition from trees and weeds, and by recycling nutrients. Burning is not practical or possible in all situations, as in small lots or within the city limits. Check with your local fire department to see if burning is allowed, and to get the required permits. Burning in April or early May is most advantageous to warm-season prairie plants, because it reduces competition with weeds and the soil heats up more quickly. Most prairies have only portions burned yearly in a cycle where complete burning takes several years. This partial burning fosters survival of overwintering insects that are lying dormant in the form of eggs or cocoons. It also leaves food and shelter for birds. Though burning is quite effective, it is not recommended until at least the third year after planting.
Mowing and removing clippings is a good substitute for burning, particularly on smaller sites. If you start a prairie from seed, mowing is recommended during the first year to control weeds which grow more quickly than prairie plants. For the first few years, set the mower high (4" to 8") to avoid cutting desirable prairie plants. After 4 or 5 years, mowing once a year after the seeds have fallen, or preferably, in the early spring. Remove clippings to expose crowns for regrowth.
Prairie usually needs no herbicides, insecticides, or fertilizers. Dense prairie vegetation will discourage invading weeds although perennial grasses from adjacent turf can invade along the edges of the planting. The wildflowers will provide food for beneficial insects which will aid in controlling pest insect populations.
For additional help in establishing and maintaining your prairie, consult the references below as well as private landscaping companies and, in some midwestern states, the Department of Transportation. For your own enjoyment, take photos from of same spot, on the same dates, several times a year, for several years. This will show you how far your prairie garden has progressed. Note how it changes through the year, including new and different creatures that your garden has attracted. Don't be surprised to see butterflies and native birds like goldfinches. Enjoy the benefits of restoring part of the landscape to what it was not so long ago.
For further information
Art, H. 1991. The Wildflower Gardener's Guide: Midwest, Great Plains, and Canadian prairies edition. Garden Way Publishing: Story Communications, Pownal, Vt.
Bohnen, J., and A. Hanchek. 1996. Prairie Seeds and Seedling Identification. MES Slide Set, University of Minnesota, St. Paul, Minn.
Daniels, S. 1995. The Wild Lawn Handbook: alternatives to the traditional lawn. MacMillan Co., N.Y.
Henderson, C.L. 1987. Landscaping for Wildlife. Minnesota Department of Natural Resources. St. Paul, Minn.
Madson, J., and F. Oberle. 1993. Tallgrass Prairie. Falcon Press Publishing Company, Inc. Helena, Mont.
Moyle J., and E. Moyle. 1977. Northern Wildflowers, a guide to the Minnesota Region. University of Minnesota Press. Minneapolis, Minn.
Peterson, R. T., and M. McKenny. 1968. A Field Guide to Wildflowers, Northeastern/North Central North America. Houghton Mifflin Company, Boston, Mass.
Robison, R., D. B.White and M. H. Meyer. 1995. Plants in Prairie Communities. FO-3238. Minnesota Extension Service, University of Minnesota, St. Paul, Minn.
Rock, H. 1971. Prairie Propagation Handbook. Wehr Nature Center, 5879 S. 92nd, St. Hales Corners, Wis.
Runkel, S. T., and D. M. Roosa. 1989. Wildflowers of the Tallgrass Prairie. Iowa State University. Ames, Ia.
Shirley, S. 1994. Restoring the Tallgrass Prairie; an illustrated manual for Iowa and the Upper Midwest. University of Iowa Press, Iowa City, Ia.
Smith, J. R., and B. Smith. 1980. The Prairie Garden: 70 Native Plants You Can Grow in Town or Country. The University of Wisconsin Press, Madison, Wis.
Smith, W. 1993. Orchids of Minnesota. Department of Natural Resources. St. Paul, Minn.
Van Breuggen, T. 1992. Wildflowers, grasses, and other plants of the Northern Plains and Black Hills, 4th edition. Fenske Printing Company, Rapid City, S. Dak.
Vance, F. R., J. L. Jowsey, and J. S. McLean. 1984. Wildflowers of the Northern Great Plains. University of Minnesota Press, St. Paul, Minn.
Weaver, J. E. 1954. The North American Prairie. Johnsen Publishing Company, Lincoln, Neb.
Wilson, J. 1992. Landscaping with Wildflowers. Houghton Mifflin Co., N.Y.
Sources of seeds, plants, and information for prairie plantings
Albert Lea Seed House
P.O. Box 127
Albert Lea, MN 56607
Feder's Prairie Seed Company
Route 1, Box 41
Blue Earth, MN 56013
Ferndale Nursery and Greenhouse
P.O. Box 27
Askov, MN 55704
Henry Field's Seed and Nursery Co.
Shenandoah, IA 61602
R.R. 2, Box 153
Fertile, MN 56540
Landscape Alternatives, Inc.
1705 St. Albans Street
Roseville, MN 55113
4838 Douglas Avenue
Racine, WI 53402
Mohn Frontier Seed and Nursery
Route 1, Box 152
Cottonwood, MN 56229
Norfarm Seed Company
P.O. Box 725
Bemidji, MN 56601
3557 E. Bregnedalgade Street
Askov, MN 55704
Prairie Hill Wildflowers
Route 1, Box 191-A
Ellendale, MN 56026
Prairie Moon Nursery
Route 3, Box 163
Winona, MN 55987
P.O. Box 306
Westfield, WI 53964
Prairie Restoration Inc.
P.O. Box 327
Princeton, MN 55371
Prairie RiDGe Nursery
R.R. 2, 9738 Overland Rd.
Mt. Horeb, WI 53572-2832
Prairie Seed Source
P.O. Box 83
North Lake, WI 53064-0083
Stock Seed Farms
28008 Mill Road
Murdock, NE 68407
Route 3, Box 178
Owatonna, MN 55060
Wildlife Nurseries, Inc.
P.O. Box 2724
Oshkosh, WI 54903-2724
Table 1. Prairie wildflowers and grasses
|Name||Flower color||Flowering date||Height|
|wild lupine (Lupinus perennis)||blue||May - June||1-2'|
|purple coneflower (Echinacea purpurea)||purple||June - Sept.||2-4'|
|meadow blazing star (Liatris pycnostachya)||purple||Aug. - Sept.||2-4'|
|prairie phlox (Phlox pilosa)||pink/purple||May - July||1-3'|
|blue false indigo (Baptisia australis) tralis)||blue||June - July||2-5'|
|butterfly weed (Asclepias tuberosa)||orange-red||July - Aug.||1-2'|
|black-eyed Susan (Rudbeckia hirta)||yellow||July - Aug.||2-3'|
|grey-headed coneflower (Ratibida pinnata)||yellow||July - Sept.||3-6'|
|large-flowered beardtongue (Penstemon grandiflorus)||pink/purple||May - June||2-3'|
|hoary puccoon (Lithospermum canescens)||orange||May - June||1-2'|
|big bluestem (Andropogon gerardii)||bronze; bluish stems||Aug. - Sept.||3-8'|
|little bluestem (Schizachyrium scoparium)||white; bluish stems||Aug. - Sept.||2-4'|
|sideoats grama (Bouteloua curtipendula)||orange-purple||July - Sept.||1-3'|
|Indian grass (Sorghastrum nutans)||golden-brown||Aug. - Sept.||3-6'|
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FO-06748 Reviewed 1997