Prairie Plants and their Use in the Landscape
Neil Diboll, Prairie Nursery
The interest in utilizing our native prairie grasses and wildflowers in the landscape has been growing at a rapid rate in recent years. Their primary attraction is that there is a wide selection of showy flowers and ornamental grasses that can be used in a variety of situations with a minimum of maintenance. There is also little or no need to use chemicals in the prairie landscape. Once established, they require no fertilizing, no watering, no spraying, little weeding, and only annual mowing. There are prairie plants for dry soils, regular soils, and moist soils. A succession of bloom from spring into fall is typical of the prairie flowers, and the late season color of the grasses provides interest well into the winter. Butterflies and hummingbirds are also attracted to the flowers, and songbirds utilize the ripening seeds in the fall. The overall effect is a dynamic, ever-changing landscape that reflects the rhythm of the seasons, year after year.
Originally, prairie plantings were installed by ecologists whose primary interest was to preserve these plants from impending extirpation, while re-creating meadows that represented the vast grasslands that once blanketed the Midwest with an ocean of colors and textures. Only 150 years ago, prairies stretched as far as the eye could see in many parts of America's heartland. Today, it is considered to be one of the rarest plant associations on the continent. The soil that the deep-rooted prairie grasses and flowers had created over the centuries was so fertile that it was systematically converted into cropland, leaving only a few small fragments in the odd corners where the plow did not reach. In a matter of a few decades, corn and wheat had replaced a complex and unique plant community. The prairie was almost completely destroyed before it could be studied and fully appreciated.
The first large scale restoration of a Midwestern prairie was undertaken in the 1930's at the University of Wisconsin under the direction of the great conservationist, Aldo Leopold. Over the next two decades, many more acres of native prairie were installed at the University of Wisconsin Arboretum. Soon other universities, nature centers and wildlife refuges were collecting and planting seeds to establish their own prairies. It was not until the 1970's, however, that many of these plants and seeds became commercially available. Since then, interest has grown steadily, more and more people have discovered these wonderful and durable plants.
Prairie Nursery was one of the first nurseries to offer a wide selection of prairie wildflowers and grasses. Begun in 1972 by J. Robert Smith, it has grown from a small garden plot to become a major supplier of native plants and seeds. True to the roots of the prairie "movement," Mr. Smith and the present owner, Neil Diboll, are both ecologists. The goal at Prairie Nursery is to do more than just grow rare and unusual plants. The guiding philosophy is to preserve a diverse "gene pool," and thus the genetic integrity that is reflected in the variability and adaptability of Nature itself. Rather than focusing on specific selections or varieties, the goal is to draw upon as many different sources as possible for each plant species. This helps to ensure that the plants and seeds will have the capacity to adapt to a wide variety of situations, which is critical to success in low-maintenance natural landscaping.
Over the centuries, the native prairie plants have evolved to survive the extreme conditions that occur in the Upper Midwest. They have had to deal with disease, drought, searing summer heat, severe winters, and the ravages of grazing by vast herds of bison and elk. In response to these calamities, prairies plants have developed root systems that are double or triple the size of their above ground growth. These large below-ground reserves of energy allow the plants to survive unfavorable conditions and recover from damage rapidly. The prairie grasses produce a thick mat of finely divided roots in the upper three to four feet of the soil, with some extending as far as nine feet deep in their search for moisture and nutrients. In order to compete with the grasses, many of the prairie flowers have root systems that extend far below those of the grasses, up to 15 feet and more in some cases. Others have enlarged underground storage organs such as bulbs, corms and rhizomes that allow them to endure periods of severe stress. By partitioning the soil environment in this way, the grasses and flowers coexist side by side and make maximum use of all available space.
In addition to sharing the soil environment, prairie plants also sub-divide the growing season among themselves. Some experience peak activity in spring, some in summer, and others in early fall. The average height of the plants in flower also increases as the season progresses, with taller flowers coming up over the earlier blooming, shorter members of the community. Many of the spring-blooming prairie flowers go dormant or near-dormant by mid-summer, making way for the coneflowers, blazingstars, sunflowers, and myriad of other summer bloomers. Following this mid-summer exposition, the asters, goldenrods, and gentians attain prominence in the season's floral finale. Then, with the first frost, the various grasses don their winter plumage of bronze-reds and golden straw colors to conclude the year's activity. In this way, many different plants can occupy a given area, with each contributing to the successive waves of color that wash across the prairie landscape each season.
When one thinks of a prairie, the image of a seemingly endless meadow rolling toward the horizon comes to mind. Prairie plants themselves, however, can be used in a variety of situations, from gardens a few square feet in size to plantings of many hundred acres. Almost all of the prairie plants can be used effectively in borders, either mixed with other perennials or as a "pure prairie" garden. A common application is to create a small meadow of one acre or less in size, often to replace a lawn area in order to relieve the owner of the cost and tedium of maintaining vast expanses of turf. As many people have discovered, their prairie meadow offers them a far more exciting landscape than their lawn, and at a fraction of the long term cost. One of the other great advantages of prairie plants is that there is a wide variety of flowers for dry soils and also for moist soils, which often present landscaping dilemmas for less durable, traditional landscape material. Many of the shorter species are excellent candidates for rock gardens. A combination of the showier flowers make a very effective butterfly garden, and in areas with appropriate surrounding habitat, they can also bring in hummingbirds. A large number of the flowers and grasses provide both nutritious seeds and protective cover that are heavily utilized by a diversity of songbirds. Even a small planting of only a few hundred square feet can become a focal point for many of these delightful garden visitors.
Prairie meadows can be established using plants or seeds, or a combination of the two. small areas of a thousand square feet or less can be easily installed using plants. A general rule of thumb is to give each plant one square foot of space, although some require less and others more. With transplants, the exact relationship of each plant to the others can be specified, allowing the designer to develop certain desired combinations and effects. Most transplants will bloom the year they are installed, but a few very long-lived varieties may require two years or more to reach maturity. It is not unusual for many of these plants to live for 25 years or longer. A large proportion of prairie plants reproduce vegetatively, producing off shoots that live on after the original portion of the plant may have died. This allows them to reproduce within the confines of the prairie sod, where openings for seeds to become established are often not available. This is why annual and biennial weeds, which require a disturbed soil environment to prosper, seldom persist in a mature prairie planting.
Seeding is somewhat trickier than transplanting and inevitably results in a more random effect. It is by far the most cost effective method for planting large areas, but requires longer to reach maturity. Many prairie seeds grow readily on an open seedbed, while some require very specific conditions for germination and growth. This is why plants and seed are sometimes used in conjunction with one another. First the seeds are planted. Then transplants of the more difficult to grow species are installed, either directly following seeding, or one or two years later, after the seeded area has become established.
The first year after seeding a prairie planting, many people are exasperated when all they see is a field of weeds! But there is no reason for despair, as these denizens of the prairie concentrate first on building their tremendous root systems. In the first year, many of the seedlings may only grow to one or two inches in height, yet have roots well over a foot long. By the second year, biennials such as black eyed Susan will make their appearance, and a few of the faster-growing perennial prairie flowers and grasses may bloom. In the third year, many different flowers will reach maturity and weeds should become less abundant as the native vegetation begins to take hold in earnest and squeeze out the undesirable elements. By the fourth and fifth years, with a small amount of management (burning, or mowing and raking in mid-spring), the prairie plants should be in full control and well on their way to forming a long-term, self-sustaining community. As with any investment, patience is required in order to reap the benefits. Five years is not long to wait for a landscape that will last a lifetime.
CHARACTERISTICS OF DIFFERENT TYPES OF PRAIRIE COMMUNITIES
There are prairie plants for almost any type of soil, be it dry, medium or moist. The shorter varieties tend to occur on dry, sandy or gravelly soils, since these soils generally possess lower levels of moisture and nutrients and cannot support the needs of most larger plants. Heights range from a few inches up to three or four feet tall. Some of the deeper-rooted taller flowers and grasses can also grow on dry soils, but the shorter ones tend to predominate and many are restricted to this environment. A high proportion of spring and fall-blooming species are common to dry prairies, since higher moisture levels and lower temperatures provide better growing conditions during these seasons. Soil moisture often becomes limiting during the heat of summer on dry soils, and only those plants with very deep roots or special adaptations can remain active. Nevertheless, a good selection of summer-blooming flowers are available for dry soils. Low-nutrient dry soils are often the easiest to successfully seed to native flowers and grasses because they do not encourage the growth of large weeds that can overtop the young seedlings and retard their growth. Fertile soils are often subject to heavy weed growth in the early stages of establishment and usually require mowing to a height of six inches once or twice in the first year to allow light to reach the prairie seedlings below.
The widest selection of prairie flowers grow on well-drained medium or "mesic" soils, such as sandy loams, silt loams, and clay loams. Mesic soils were home to the tallgrass prairie, whose thick, deep roots built the rich soils of the Corn Belt. These soils have sufficient water and nutrient-holding capacities to support most of the taller flowers, and many of the shorter varieties will grow well on these sites as well. Most range in height from two to five feet, with a few that will reach six feet or more. Due to the ability of mesic soils to supply good levels of moisture well into the growing season, blooming activity peaks during the long hot days of summer. This explosion of color in June, July and August is the hallmark of the mesic prairie. When most of the wildflower gardener's woodland flowers have finished blooming, are the lawn is threatening to call it quits without its daily dose from the sprinkler, there stand the prairie flowers in their greatest glory! With roots that reach deep down into the soil to find moisture, they make summer a time of floral opulence without a lot of indulgence.
In the zone of transition that occurs between wetlands and the upland prairie, one encounters the moist prairie. Here are found some of the grandest and most robust of all our native herbaceous perennials, along with some of the showiest. The Queen of the Prairie, Cardinal Flower, Turk's Cap Lily, Prairie Blazingstar, New England Aster and many other beauties make their home here. Most members of the wet prairie community grow to four or five feet, but a few can reach as high as eight to ten feet tall. The availability of plentiful moisture encourages lush growth throughout the summer. Because wet soils are slow to warm up in spring, most floral activity occurs later in the season, from mid-summer into early autumn. Many of these plants are capable of withstanding extended periods of flooding when dormant (from late fall until early spring) and are ideal for landscaping along pond edges and streambanks. However, most of them require an unsaturated, aerated zone in the upper soil during the growing season, and should not be planted in areas that experience standing water all year long. They will also thrive in a rich garden soil that is supplied with sufficient moisture, and some are capable of growing on mesic soils as well.
With this diversity of native plant material, suitable for a variety of applications, it is clear why the use of prairie plants is growing rapidly. The prairie landscape continues to captivate people's imaginations today as it has for hundreds of years. The Plains Indians sang songs for each of the flowers that grew on the prairie and handed them down from generation to generation. When the early European and American explorers encountered the grandeur of these grasslands, their fascination with them is reflected in their written accounts. W. R. Smith described his impressions from atop Belmont Mound in southwestern Wisconsin in 1837:
The view from this mound beggars all description. An ocean of prairie surrounds the spectator. This great sea of verdure is interspersed with delightfully varying undulations, like the vast waves of the ocean, and every here and there, sinking in the hollows or cresting the swells, appears spots of trees, as if planted by the hand of art for the purpose of ornamenting this naturally splendid scene.
D. D. Owen wrote in 1848:
On the summit levels spreads the wide prairie, decked with flowers of the gayest hue; its long and undulating waves stretching away till sky and meadow mingle in the distant horizon.
Although little now remains of these once-vast flower gardens, the plants that composed them live on. Today, we can incorporate these beautiful flowers and grasses into our own landscapes and enjoy their constantly changing parade of color year after year. And with all the time saved on maintenance, that leaves that much more time for enjoyment!
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