Considerations for Prairie Plant Species Selection

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Considerations for Prairie Plant Species Selection

Prairie plantings are perennial vegetation systems which do not require yearly seeding. The selection of appropriate prairie species is important in order to attain desired goals, aid establishment, and reduce yearly maintenance. Prairie species native to your location or adapted to the environmental conditions in your area should be selected. The STRIPS team is not prescriptive in their seed mix recommendations; however, landowners are encouraged to consider several factors when making species selection decisions, as described below.

Photo by Anna McDonald

Achievable

Select seed mixes which are financially reasonable. Seed mixes can range from $100 per acre to $2,000 per acre. It is important to select prairie species which meet the goals of the farmer and landowner, as well as program requirements while also providing affordability for the client.

Adapted

Select prairie plant species which are adapted to the climate and soil conditions in your target growing area. Key features to consider are day length, maximum and minimum seasonal temperatures, drainage, and precipitation.

Diverse

Select diverse seed mixes which contain a variety of grasses, sedges, and both leguminous and non-leguminous forbs. Forbs should be predominantly perennial to provide strength to the planting and offer long lasting ground cover. Diverse mixes will increase the diversity of the wildlife and insect populations. Increase diversity by including plant species from these categories in following proportions:
- ~50% Grasses/Sedges
  - warm-season grasses
  - cool-season grasses
  - sedges
- ~50% Forbs
  - non-legumes
  - legumes
Mixes composed of about 50% grasses and 50% forbs establish quickly and are good at keeping weeds out. Mixes that contain a lot of forbs will increase the cost per acre for establishment but will also encourage greater wildlife diversity. A good way to reduce cost when planning the seed mix, while still maintaining a high diversity seed mix is to exclude the most expensive forbs.

Considerations for Seeding Rate

Prairie strips should be planted with a rate of forty seeds per square foot to prevent weeds from invading. Ideally, forbs should be seeded at twenty seeds per square foot and grasses at twenty seeds per square foot.
When seeding on steep slopes (>3:1), seeding rate should be increased by 30-50% because of potential loss due to erosion.
Time of planting can affect seed germination rates. When seeding in winter, increase the seeds per square foot of warm-season grasses (except those with thick seed coats like switch grass) by 50% due to increased seed mortality.
Seeding method can affect seed germination rates. Seeding rates should be increased when using a broadcast seeding method to account for loss due to predation and poorer seed to soil contact.

The UNI Tallgrass Prairie Center offers a helpful Designing Seed Mixes guide showing an example seed mix and corresponding seeding rates for each species.

Keeping Goals in Mind

Consideration should be given to the goal of establishing a robust mix of species when selecting seed varieties. While the short-term seed cost might be a bit higher, one substantial benefit of increasing the number of prairie species planted is that a wide range of species with diverse functional characteristics will typically results in the presence of fewer weed species.

Functional Characteristic Considerations:

Stems

Select prairie species that are stiff-stemmed and stay upright even during heavy downpours and driving rain.

Roots

Include deep-rooting prairie plants; some have a rooting depth of 10 to 15 feet. In addition to holding soil, deep-rooting plants can also access and hold nutrients and water within the soil profile differently than other plants.

Bloom time

Prairie plant species will mature, and flower at different times throughout the growing season. Select prairie plants with different bloom times throughout the season. The staggering of bloom time will provide an increase in aesthetic value by having something in bloom most of the time. This will also extend the amount and duration of floral resources for pollinators and other wildlife. THIS POSTER depicts common prairie wildflower species in Iowa according to their bloom period.

Growth habits

Each plant species has its own unique growth habits. Select prairie plant species which exhibit a range of structural diversity that supports wildlife and functional diversity.

Height

Select plant species which range from short to tall. The variation in height will provide diverse habitat as well as slow the movement of wind and water

Life cycle

Prairies are dominated by perennial vegetation. A diverse mix of perennial, biennial, and annual plant species should be selected to ensure year- round cover.

Form

Plant species exhibit an array of growth forms such as spreading, vining, upright, clump, and bunch. Selecting prairie plant species with different growth forms will increase the benefits of the prairie.

Prairie Plant Species Recommendations:

Iowa Prairie Seed Calculator: The University of Northern Iowa Tallgrass Prairie Center is an advocate for the use of native vegetation to provide public benefits. The Tallgrass Prairie Center assists in roadside vegetation management, native source identified seed development, and prairie advocacy. The Iowa Prairie Seed Calculator is a tool supported by the University of Northern Iowa Tallgrass Prairie Center and can be used to determine species mixes, seeding rates, cost, and other helpful information.

Plant Iowa Native: Is a resource website which provides information on native vegetation, restoration, incentive programs and more.

NRCS and FSA Programs: If the prairie strips are being funded through a government program the program will most likely require the use of a specific seed mix and these requirements should be followed.

Pre-Mixes: Many reputable seed companies offer pre-mixes of a variety of prairie species which are easy to use and meet various government program requirements. These are typically the best option to ensure compliance with governmental programs.

Ways to purchase seed:

Seed Companies:

Many companies specialize in and sell native prairie seeds. The Iowa Seed Directory can be used by prospective seed buyers to locate seed or contact your regional prairie restoration contractor or NRCS office.