Nursery Market Report – Prairie Plantings

In the landscape, prairies are an endangered species. In fact, more than 99 percent of the Midwest’s tallgrass prairies have been converted to cities and highways. For this reason, and because of their beauty and charm, interest in prairies soars.

Prairies are striking for many reasons – namely their native grasses and wildflowers, such as coneflowers, prairie phlox, false indigo and orchids, which attract birds, butterflies and other wildlife. Prairies also pique the interest of property owners and managers because they often take less time and expense to maintain than conventional lawns. They reduce use of pesticides, fertilizers and mowing.

Even though prairies aren’t native to all regions, they can be created in most areas, and management includes removing weeds and woody plants that compete with prairie plants for water, light and space. This introduction to prairies from the University of Minnesota Extension, Saint Paul, Minn., will help you learn how to establish them in the landscape.

SELECTING A SITE. Prairie plants grow best in full sun and open spaces. When selecting a site, look for areas with maximum sun exposure and minimal root competition from trees. Ash, basswood and maple trees provide more competition for prairie plants because they have many surface roots that compete for water and nutrients. Prairie plants often are more compatible with bur or white oak.

In particular, knowing your soil type and surface drainage is important when selecting prairie plants. Native prairie soils vary greatly in composition, from dry, gravelly, sandy soils that hold little moisture to silty or heavy clay soils that can hold excessive water. Poorly drained soils should be avoided.

Also important in site selection is determining whether there are weed ordinances in the city in which you work. These ordinances were originally designed to keep yards more attractive and to control the spread of noxious weeds. Ordinances vary from one city to another, so call your city government to find out the specifics for your community.

In addition, consider using some elements of care, such as mowed edges or edging near the prairie planting to show the area is meant to be there. And because 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 item.

PREPARING THE SITE. First, remove all existing vegetation. If you try to scatter seeds or put young plants into existing vegetation, you will have a low likelihood of success because of plant competition. Then, there are several ways to establish a prairie in an existing area of 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 easier to remove. Once the vegetation is dead, till the area thoroughly. This method 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 inches and rake to create a uniform, fine seedbed.

A third method involves using a nonselective herbicide containing glyphosate to kill existing vegetation. As with all herbicides, read and follow label directions. When the vegetation has died in about two weeks, till to a depth of 12 inches or more. If a slit seeder will be used, the dead vegetation can be mowed to a 1- to 2-inch stubble. This dead mat of roots and sod may act as a mulch and prevent excessive weed growth.

PLANTS VS. SEEDS. You can start a prairie from seeds or plants. 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 they establish quickly and may flower the first year. Also, some species are available only as live plants.

Always select plants with your site’s characteristics in mind. Include grasses because they provide physical support, weed competition, protection for wildflowers and a source of food and shelter for birds during winter (for a list of common prairie plants, see sidebar, left).

If you use “prairie-in-a-can” mixes, which are available from a variety of sources, they often contain marginally hardy perennial and annual species that don’t return in subsequent years. Better results may be achieved by using mixes created for your area by local seed dealers.

If you are using seed, even distribution and good seed to soil contact are vital for successful germination. Broadcast seed by hand or use a spreader. For small seeds, mix with a bulking agent, like clean sand or dry sawdust, for more uniform seeding. Seed slowly and make passes from two different directions. As a general rule, use ½ pound of grass seed per 1,000 square feet and two ounces of wildflower seed per 1,000 square feet, or instructions on seeding rates can be obtained when purchasing seeds.

Watering after seeding improves germination, but is not essential. Covering with a thin mulch of clean straw prevents drying out, reduces exposure to wind and animals and helps prevent erosion on slopes.