By Tamara Metzen, Master Gardener Intern Tamara.firstname.lastname@example.org
Since I was a child growing up in rural southeast North Dakota in the 1970s, I have always enjoyed exploring the landscape, even though the area where I lived was mostly farmland. I pretended that I was living in the era of Laura Ingalls Wilder who, along with her family, moved onto the Great Plains when it was an uncultivated expanse of native prairie grasses and flowers (Fig 1). I clearly remember the opening scenes of the tv show, Little House on the Prairie, where Laura and her sisters are running across the landscape through the tall, waving grasses. However, there were very few native prairie meadows where I lived. The few wild flowers I remember were Canadian anenome (Anemone canadensis) growing in the ditches, prairie phlox (Phlox pilosa) peeking out of the edges of shelterbelts and occasional prairie roses (Rosa arkansana) (Fig 2) hiding under fence lines where the plows couldn’t reach them. At home, my mother was known for her hybrid irises and daylilies which were beautiful but a little ostentatious for me.
In 1988, my husband and I moved to a rural farmstead near the Sheyenne River Valley (Fig 3). Working in the public education field, I had the summers to explore. I began to take excursions into public lands and started to notice the subtle beauty of the plants. I purchased several native prairie identification books and was soon able to recognize common species and began searching for those that were less common and even rare. I noted blazing star (Liatris pycnostachya) (Fig 4), purple cone flower (Echinacea purpurea), and wild bergamot (Monarda fistulosa). I also searched for prairie smoke (Geum triflorum), closed gentian (Gentiana andrewsii), pasque flower (Anemone patens), marsh marigold (Caltha palustris), blue-eyed grass (Sisyrinchium angustifolium) and the wood lily (Lilium philadelphicum). I never did locate the endangered white fringed prairie orchid (Platanthera blephariglottis). As I learned to appreciate these plants in their native habitats and the ecological role that they play, I also developed an interest in growing them.
I attempted to propagate the more common native prairie flowers into my own flower beds, often with disappointing results. At the time, I was not overly concerned about digging up common species for my garden. I later learned that, in many states, there are laws about protecting native plants. In fact, species that are on state or federal threatened and endangered lists cannot even have their seeds, or any parts, collected without a permit. In addition, I know now that very few native plants tolerate being dug up as their roots are uncommonly deep, having to compete with native prairie grasses in times of drought. One of the few I did get to grow was spiderwort (Tradescantia bracteata), which became a real nuisance in my garden, as it tended to reseed prolifically.
More recently, in 2017, my husband and I moved to his family farmstead near Milnor, ND. Behind the old barn is a one-acre site that was an old dairy cattle yard. It had been planted in non-native grasses with very little species diversity. The soil is very sandy with a gravelly base, being on the western edge of the Red River Valley on the shores of ancient Lake Agassiz. This area would have been considered the transition zone where the tall grass prairie meets the mixed grass prairie. When we built our new home, we used about ½ acre of the cattle yard to build a drain field for our septic system. This area quickly grew into a weed patch that needed to be mowed at least weekly once the soil had been disturbed. Tired of looking at a field of weeds, I talked my husband into replanting the area into native prairie.
Although many native plants will tolerate a variety of soils and moisture levels, it is a good idea to determine the general soil type and soil moisture for the intended planting area and to select the species that are best adapted to these conditions. It is also wise to locate locally-grown seed and plants, so that their genetics would be suitable for the climate and soil conditions that we have. Do not plant naturalized species that are known to be invasive. Some species, for example purple loosestrife (Lythrum salicaria) (Fig 5), have been outlawed in many states because it is an invasive species in waterways.
I consulted with Mathew Olson from the Sargent County Soil Conservation District. He recommended Milborn Seeds, Brookings, SD, as a good source. I ordered the Little Country Native Mix which was designed with grass species suitable for both wildlife and landscaping purposes. In addition, many of the grasses are bunch grasses that grow in clumps and will not provide too much competition for the wildflowers. Sod-forming grasses, which are often used in lawns, would be less desirable in a wildflower meadow for this reason. The grass species and the percentage of each in the mix included 30% little bluestem (Schizachyrium scoparium), 20% blue grama (Bouteloua gracilis), 20% side oats grama (Bouteloua curtipendula), 5% prairie dropseed (Sporobolus heterolepis), 10% Virginia wildrye (Elymus virginicus), 10% slender wheatgrass (Apropyron trachycaulum) and 5% prairie June grass (Koeleria cristata). Because I was interested in establishing native wildflowers for both their beauty and for their pollinator benefit, I also included the Native Forbs mix which included 12% black-eyed Susan (Rudbeckia hirta), 9% prairie coneflower (Ratibida columnifera), 9% purple coneflower (Echinacea purpurea), 8% evening primrose (Oenothera speciosa), 8% western yarrow (Achilea millefolium var. occidentalis), 6% white prairie clover (Dalea candidum), 6% wild bergamot (Monarda fistulosa), 5% plains coreopsis (Coreopsis tinctoria), 4% Canada milkvetch (Astragalus canadensis), 4% hoary vervain (Verbena stricta), 3% blanket flower (Gaillardia aristata), 2% false sunflower (Heliopsis helianthoides), 2% grayhead coneflower (Ratibida pinnata), 2% Illinois bundle flower (Desmanthus illinoensis), 2% Indian blanket (Gaillardia pulchella), 2% Maximillian sunflower (Helianthus maxmilliani), 2% New England aster (Symphyotrichum novae-angliae), 2% partridge pea (Chamaecrista fasciculata), 1% common milkweed (Asclepius syriaca), and 1% Rocky Mountain Bee Plant (Cleome serrulata). Some of the grass and wildflower species in the mix are not local but I compromised due to the lower cost for a mix of species rather than purchasing them individually. I searched the internet for other relatively local sources of seed and found Prairie Moon Nursery based in Winona, Minnesota. They offer individual seed packets for $2.00. I ordered packets of Canada anemone (Anemone canadensis), pasque flower (Anemone patens), bottle gentian (Gentiana andrewsii), smooth blue aster (Symphyotrichum laeve), prairie blue-eyed grass (Sisyrinchium campestre), early buttercup (Ranunculus fascicularis), common blue-eyed grass (Sisyrinchium albidum), Joe Pye Weed (Eutrochium maculatum), prairie onion (Allium stellatum), prairie smoke (Geum triflorum), prairie spiderwort (Tradescantia bracteata), prairie larkspur (Delphinium virescens), tall larkspur (Delphinium exaltatum), butterfly weed (Asclepias tuberosa), queen of the prairie (Filipendula rubra), blue wild indigo (Baptisia australis), Maxmilian’s sunflower (Helianthus maximilianii), dotted blazing star (Liatris punctata), harebell (Campanula rotundifolia), golden alexander (Zizia aurea), and showy beardtongue (Penstemon cobaea). It was important for me to choose a variety of species to attract a diversity of pollinators and to provide pollen and nectar sources from early spring to late fall. Sources recommended that at least three flowering species per season from early spring to late fall should be planted.
Once the seeds from Prairie Moon Nursery arrived, I read individual packet directions, realizing that the majority of the seed required 30-120 days of cold stratification. This was ideal, as they were going to be planted in the fall with all winter to remain dormant. If I had waited to seed until spring, the seeds that required cold stratification should have been sowed in growing media and placed in the refrigerator for the appropriate time period. In addition, wild blue indigo was leguminous and needed the addition of soil inoculants containing rhizobia bacteria which was included but required an additional step to prepare before planting. I did not purchase species that required scarification, heat treatment or light treatment although some native species may need one of these treatments to germinate. I planned to plant the seeds of these individual species in marked 4 foot square trial areas on the edge of the ½ acre site to determine germination rates of each and to transplant the seedlings throughout the site once they were growing well next spring or summer.
Removing existing vegetation from the planting site was recommended so that it would not compete with the desired varieties. Although it is nearly impossible to remove all weed seeds from the seed-bank, it was most important to kill the perennial weeds before I seeded. My first plan was to cover the planting site with black plastic to smother the weeds (old carpeting or thick sections of newspaper were also suggested), but my husband quickly dissuaded me from doing this. Another method to prepare the site would have been sod-cutting to remove the top 2-3 inches of grass and soil and then lightly tilling the cleared area. Burning along with cultivation and mowing is also a possible method of preparing the site. However, outdoor burning regulations should be followed and the local fire department should be informed of any controlled burn. In my situation, it was much easier to kill the weeds with Roundup (a.i. glyphosate) when the weeds were actively growing. In late August, we sprayed the area on a windless day using our all-terrain vehicle with a sprayer attached. Four weeks later we sprayed again for the surviving weeds.
Now it was time to seed the area. I could have chosen to seed mechanically with a drill seeder, but I decided to hand broadcast this small area. A week before I seeded, my husband loosened up the top soil with a pull-behind spring tooth harrow. The seed bed needed to be free of rocks or soil clumps more than 2 inches in diameter. I wanted to broadcast the seed late in the season (dormant seeding) when the ground was below 40 degrees Fahrenheit to prevent germination, but in the middle of October an early snow storm was to arrive. I seeded on October 10th, and on October 11th, we received 2 inches of rain and on October 13th 6 inches of snow. In dormant seeding, it is important to seed late enough so that the seeds will not germinate before winter comes, which luckily did not occur in my case. In support of this timing, wildflowers seeds have increased germination in spring after a fall planting because it takes advantage of the cold, moist conditions, helps break seed dormancy and promotes earlier germination and faster seedling establishment the next spring. Seedling establishment is especially important when planting in sandy soils which heat up and dry out quickly in the spring. However, it may also be important on clay soils, because this soil type tends to become rock-hard when it dries out and restricts the seedlings’ root development in the spring. Wet clay soils may cause difficulty in working the soil in the spring, so there are many benefits for dormant seeding. On the other hand, waiting for a spring planting (with soil temperatures about 60 °F) may benefit warm season grasses such as little bluestem which often show higher germination rates when planted in late spring or early summer compared to fall seeding. If a mix of cool and warm season grasses is used, the soil temperature should be 50 °F at minimum. As a precaution, warm season grasses should never be planted in late summer to early fall as the seedlings could germinate but would likely not survive the winter. One source even recommended using perennial grass and wildflower plugs which could be started a year ahead of being planted in a site, but this process sounded much more time consuming and complicated to attempt.
When broadcast seeding, a seeding rate at least 50% higher than drilling rate is suggested. The general rate of 5-20 lbs. of live seeds per acre was recommended to broadcast for the grasses and 6-7 lbs. of wildflower seeds per acre were suggested to mix in, which the source said would yield about 10-20 seeds per square foot. If planting an area over an acre, mechanically planting the area using a broadcast or no-till seeder is a good idea. A broadcast seeder would spread the seed over the soil evenly while the no-till seeder would plant the seed in rows. If a seeder is used, the seed should be planted at a shallow depth of ¼ – ½ inch. Many of the species have very small seeds, so deep planting may result in failure to grow. It is better to be too shallow in planting seeds rather than too deep. Having mixed the Little Country grass seed mix with the Native Forbs in a 5 gallon bucket by hand, I also added some damp sand to use as a “carrier” for the seed. Sawdust, peat moss or cracked corn could also have been used for this purpose. The amount of carrier recommended is about 2.5 feet cubed of carrier per 1,000 SF of area. When seeding it is a good idea to choose a windless day. The recommended procedure is to divide the seed mixture in half and broadcast one half of the seed evenly over the site. The second half of the seed should be broadcast over the site walking perpendicular to the initial direction for even distribution. A rake or drag is then used to cover the seed and the site should be gone over with a roller. Finally the site was covered with approximately ½ inch of weed-free oat straw the same day to help keep the soil moist for a longer period and reduce erosion, as well as preventing birds from picking up the seeds.
There will be plenty of maintenance in the coming years. If the upcoming spring is unusually dry, irrigation may be needed. Once the plants are established, they should only require rainfall. The first year, weed control will be important to reduce competition for water, light and space. It will be important to mow before the weeds have set seed. It is not recommended to pull weeds in the first year as this would disturb the developing seedlings as well as the ungerminated seed. Once established the first year, the area should be mowed approximately 3 times to a height of 4-6 inches when the majority of weeds are in flower or when the weeds reach a height of 10-12 inches. Cutting this high will allow the shorter prairie flowers to remain undisturbed. Many of the prairie plants may show little visible above-ground growth the first years as they are building their roots. An off-set flail mover is recommend to chop up the weeds when they are cut instead of laying the cut weeds on top of the prairie seedlings like a rotary mower would do. In the fall of the year, it is good to maintain the vegetation height at 8-10 inches through the winter to insulate the seedlings and to prevent frost heaving. If a prairie meadow is planted only in grasses, a selective broadleaf herbicide could be used to provide chemical weed control. Unless a soil test determines otherwise, fertilizers are not needed when planting native grasses and wildflowers, as weeds tend to respond better to them than do native species. Fertilizer application could be detrimental to the growth of some native plants, particularly those that are leguminous such as purple prairie clover.
In the second year, residual vegetation can be removed in early spring. If weeds are still growing, the area can be mowed to approximately 12 inches when the majority of weeds are in full flower but before they make seed. Additional prairie seeds may germinate over the 2nd and 3rd years after the initial planting. The planted site can also be burned after the second season every 2-3 years, but this should be done on windless days in the early spring when the dormant grass is dry but the soil is still wet. While many of the perennial prairie flowers and grasses will not flower until the 3rd or 4th full growing season as they devote most of their effort in the first years to developing their root systems, some species such as purple coneflower and black-eyed Susan likely will germinate quicker and produce flowers the first growing season. Eventually the prairie plants will establish deep root systems which will allow them to squeeze out weeds. Patience will be needed to establish a successful prairie meadow! I look forward to seeing what develops in my endeavor, and, if I am successful, I hope to establish the entire 1 acre site as a prairie meadow, learning from my mistakes as I go along.
Art, H. W. (1991). The wildflower gardener’s guide: Midwest, Great Plains, and Canadian prairies edition. Storey Communications, Pownal, Vermont.
Milborn Seeds (2019). Our roots run deep. Brookings, South Dakota.
Niering, W.A. & Olmstead, N. C. (1979). The Audubon Society field guide to North
American wildflowers: Eastern region. Alfred A. Knopf, Inc., New York.
Prairie Nursery (2019). 2019 native plant catalog and ecological gardening guide. Westfield, Wisconsin.