Tuesday, October 23, 2007

Gardening With Local Native Wildflowers

Gardening With Wildflowers

http://www.treilulele.com/?p=338

Both home gardeners and professional landscapers are showing new appreciation for the beauty of local native flowers

By Robert H. Mohlenbrock

Interest in growing wildflowers is about to come full circle from the time, around 300 b.c., that the Greek philosopher Theophrastus wrote about the virtues of plants. A student of Aristotle, Theophrastus is often regarded as the ‘father of botany’ because of the intelligent discussions of 480 kinds of plants in his Historia plantarum. Most of these plants he knew from his garden, and each of them had been brought in from the wild. Horticulture—the science of breeding plants—was unknown in those days because subjects such as genetics, which are vital to developing new varieties, had not yet been conceived. The only flowers known were wildflowers, those that occur in nature.

For centuries, native species were all that botanists had to work with, and they were valued for their beauty and for their usefulness (or harmfulness) to humankind. After horticultural varieties began to be developed and showier, more prolific forms of plants were introduced, interest in native species for the garden waned. Formal gardens featuring the ever-improved varieties that were spawned by horticulture became the rage throughout much of Europe. Eventually, formal gardening spread to the United States, and the growing of wildflowers for pleasure became a lost art.

Still, the introduction of wild species from foreign lands became a trend in some European countries. In the 18th century, American botanist John Bartram collected for shipment to England wild plants from eastern North America he thought might make worthy garden flowers. The government of France sent botanist André Michaux to the United States in 1785 to gather plants that would be suitable for French gardens. Showy native goldenrods from the eastern United States have been a standard item in English perennial gardens for several decades. Americans are just now beginning to appreciate their value as a garden flower.

As the native European flora began to dwindle from the pressures of civilization, native wildflowers were brought back into gardens not only for their beauty but in order to preserve the species. Wildflower gardens became popular in England, Switzerland, and other countries where wild plants were threatened with extinction. On the Schynige Platte, 4500 feet above the village of Interlaken in the Bernese Oberland region of Switzerland and reachable only by cog railway, the Society for the Alpine Garden has established an unusual wild garden of plants native to the alpine and upper subalpine regions of the Alps. More than 500 species of flowering plants and ferns grow in the garden, arranged according to habitat, such as meadows, heaths, and limestone-impregnated rocks.

An American Heritage

The plight of the native flora in the United States, which concerns many people today, was recognized a half century ago by a few perceptive individuals. In his book Pioneering With Wild Flowers, published in 1935, botanist George Aiken wrote that ‘native plants have been crowded back with ever increasing rapidity until now only a small fraction of their former number remains. They have seen the forests cut away, cities and villages grow up, roads made, bogs drained for agricultural programs, great reservoirs built, and with each new development they have suffered.’ He went on to note that ‘if some of them are to be saved, we must learn how to grow all worthwhile species.

Despite this early warning, few Americans realized how rapidly native plants were being destroyed. It took the passage of the federal Endangered Species Act of 1973 to increase the nation’s interest in preserving plants as part of the American natural heritage. Since much of the country is still being developed at a very rapid rate, causing the large-scale destruction of native habitats and the organisms that they harbor, there has been a surge of enthusiasm for the use of native plants in landscaping as a means of perpetuating wild species.

In fact, gardening with native species is becoming a national trend in the United States. While pursuing the commendable goal of helping to preserve the natural heritage, gardeners are developing a real appreciation for the ornamental possibilities of the local flora. There has been an upsurge among landscape architects too in the use of native plants in their designs. For example, designs incorporating attractive small native trees such as flowering dogwood and redbud increasingly grace the grounds of corporate headquarters and shopping malls, as well as homes. Nearly 400 commercial nurseries in the United States deal in wildflowers.

Wildflower gardening is generally perceived as low-maintenance gardening; this is often what attracts modern gardeners with limited time to pursue their hobby. But growing wildflowers can also be an aesthetic experience. One often feels a deeper sense of identity with the environment when growing wildflowers.

Designing a Garden

The selection of wildflowers from which a gardener can choose is nearly unending. The United States has more than 20,000 different kinds of native plants. Although a wildflower garden can include species from various parts of the country, gardens made up of flowers native to the particular region are more typical.

There are three strategies for cultivating native wildflowers. One is to incorporate them into an already existing natural habitat. Another is to introduce wildflowers into a garden of cultivated ornamentals to provide additional diversity. A third is to develop a garden of wildflowers with common habitat requirements, such as a woodland garden, alpine garden, bog garden, or prairie; the gardener chooses the type of natural setting that can best be imitated and then puts into it the wildflowers that grow best in that situation.

Climate is an important factor in determining what plants can be grown in a given place. Alpine plants do not do well at low elevations, while desert plants do poorly in rugged northern habitats. In designing a wildflower garden, a gardener must also choose plants that are appropriate for the condition of the land. Such factors as light, exposure, and the quality of the soil must be considered. It is possible to establish some type of wildflower garden in almost any setting.

In the past it was customary for gardeners to dig up wild plants and replant them in the garden, or else to purchase from commercial nurseries stock that had been dug from the wild. With native plants diminishing in number, it is now ecologically and perhaps even morally wrong to dig up wild plants unless there is absolute evidence that the area where the flowers are growing is going to be developed in a way that would destroy the plants. It is best to either collect seeds from wild plants or purchase seeds (or plants grown from wild seeds) from commercial nurseries.

The home gardener can create a good balance of species by selecting plants differing in heights, flower color, and blooming seasons.

Soil and Seed Preparation

Once the overall design of the garden has been laid out, the soil must be prepared. It is useless to purchase one of the popular wildflower seed mixes on the market and scatter the seeds over grassy or weedy areas and expect the wildflowers to come up. As in any garden, the seeds must be sown on properly prepared soil. The soil should be able to retain moisture and permit proper air circulation and drainage. If the soil is too sandy or clayey, organic matter should be added to it. The seedbed should be prepared two or three months before planting to permit the soil to settle properly. To keep weeds from overtaking the native plants, the soil should be covered with a 4-inch to 6-inch layer of mulch during this settling period. Most wildflowers grow best in neutral or slightly acid soils (pH 6.5-7.0); it might be necessary to add ground limestone if the soil is too acidic, or iron sulfate if it is too basic.

Gardeners collecting their own seeds should select a sizable colony of plants and take only a small portion of the seeds, leaving the majority in the wild population to ensure its regeneration. As soon as possible after they have been collected, the seeds should be spread out on a newspaper to dry for a few days. (Moist seeds soon become moldy.) Many seeds have extraneous matter, called chaff, associated with them. The chaff can be removed with a series of sieves or simply by hand. Freshly collected seeds may be planted immediately, or they may be stored. The seeds of some species remain viable for many years. Most wildflower seeds will germinate better if they are stored in a refrigerator soon after cleaning. They may be stored in vials, envelopes, or plastic film canisters. (Gardeners should be sure to label their collection accurately.) Some seeds, particularly those produced by fleshy fruits, should be stored between layers of sand in airtight containers in the refrigerator until the following spring. Through experience or by reading wildflower gardening books, one can learn the dormancy requirements of various seeds. Some seeds need periods of cold to break down chemicals that inhibit germination. Sometimes alternate freezing and thawing can break down hard seed coats; immersing in hot water will assist germination in other cases. Scratching or searifying (making small slits in) the seed coats so that water can be absorbed will help certain seeds.

Caring for Wildflowers

Many people think that wildflowers are hardy and require little care. If the wildflowers are growing in the wild, this may be true, but if they are part of a backyard garden, they will need about as much maintenance as the finest hybrids. When new shoots appear in early spring, they should be fertilized with manure or a standard 5-10-5 fertilizer (5 percent nitrogen, 10 percent phosphoric acid, and 5 percent potash). If plants look pale and weak in midsummer, they need to be fertilized again. Mulching in bare spots between plants will keep down weeds, but it is important that the mulch not touch the garden plants, or they will begin to rot. The mulch also keeps the soil from drying out. It is essential to water the wildflowers, particularly on sunny days, but it is equally important that the foliage not be left wet overnight. Even after a wildflower perennial has bloomed, the gardener must continue to water it.

Experience will teach one the requirements of each kind of wildflower in the garden. For example, black-eyed Susans, sunflowers, and Queen Anne’s lace grow tall and spindly if grown in soil with high organic content. Butterfly-weed needs well-drained soil and will not tolerate mulching. Wild ginger and jack-in-the-pulpit need soil that contains peat to help hold in moisture.

Many native wildflowers have the ability to adapt to new surroundings, but selecting wildflowers that are native to the area often produces the best results. A spring woodland wildflower garden in the eastern United States could include spring beauty, bloodroot, dutchman’s breeches, dwarf iris, hepatica, jack-in-the-pulpit, squirrel-corn, Virginia bluebells, trout lilies, and various kinds of trilliums. In the arid Southwest, however, a garden of Texas bluebonnet, Indian blanket, hummingbird’s trumpet, Indian paintbrush, owl’s clover, gold poppy, evening primrose, desert marigold, and a variety of penstemons would be appropriate.

Remembering the Prairies

The restoration of prairies has been the most popular activity in wild plant preservation in the central United States. This is due in part to the unique nature of prairies as a natural ecosystem, as well as to the drastic decline of prairies during the 19th century. When the first white settlers moved across central Ohio, Indiana, and Illinois and into the Great Plains, they found mile after mile of prairies dominated by a great variety of grasses and wildflowers unknown to them. Big bluestems, growing as high as 14 feet, were taller than a rider on horseback. It was soon realized, however, that the prairie soil in which the bluestems, Indian grass, and sideoats grama thrived was ideal for crops. Almost overnight, one of America’s greatest natural resources was turned into agricultural cropland where corn, wheat, and now soybeans cover continuous acres for hundreds of miles.

Recently, ‘Save the Prairie’ has become a rallying cry around which thousands of prairie enthusiasts have gathered. Today, prairies of every imaginable size are being recreated on both public and private lands. Nurseries dealing exclusively in prairie plants and their seeds have sprung up across the midwestern states. Restoration projects, such as those at the Fermi National Accelerator Laboratory and the Morton Arboretum, outside the Chicago area, provide exciting replicas of the prairies that the Midwest settlers saw.

Using prairie plants in landscaping not only helps to preserve a vanishing segment of the natural heritage, but also is economically sound. The low maintenance required of a prairie once it is established is in sharp contrast to the high cost of continuous care that lawns require. In addition, the wide variety of prairie plants permits one to select wildflowers of several colors and that bloom at different seasons, as well as species that will thrive in the particular environment. At least a quarter of an acre of land is generally needed to recreate a prairie; most private prairies are seen in areas outside cities and suburbs.

Prairie wildflowers begin blooming early in the spring with the flowering of the lovely wild hyacinth, the showy pasqueflower, and the bright puccoon. A never-ending procession of colorful blossoms continues until the first frost of the autumn and includes dozens of showy wild species such as anemones, milkweeds, wild indigos, coreopsis, coneflowers of many kinds, lupines, prairie clovers, blazing stars, asters, goldenrods, rosinweeds, prairie black-eyed Susans, and sunflowers. By planting prairie grasses among the wildflowers, the gardener achieves a continuous cover of vegetation, and the resulting blend of broad-leaved and narrow-leaved plants is pleasing to the eye.

There are prairie plants suitable for a variety of environmental conditions. Moist areas are good for wet prairie species such as prairie iris, joe-pye-weed, queen-of-the-prairie, and cup plant. Planted with prairie cordgrass, the result is pleasing, especially for a habitat that is often difficult for the gardener to deal with.

Establishing a prairie is, in many respects, not unlike developing any other garden of wild plants. But there are a few precautions. The area selected for the prairie should receive at least 75 percent sunlight, since most prairie species will not do well in the shade. Since natural prairies are dominated by grasses, a restored prairie should be too. A minimum of 50 percent of the area should be planted with grasses. Although several of the prairie restorations in the United States cover many acres, it is best for the home gardener to start on a small scale, even if ample land is available, because establishing a prairie takes a lot of time, energy, and money if one has to buy the seeds. Since grasses burn readily and rapidly, it is advisable to build a firebreak if the restored prairie is large.

A good prairie should have a sprinkling of members of the legume family (prairie clover, bush clover, or partridge pea, for example). Since legumes in nature have bacteria in nodules on their roots that produce nitrogen and enrich the soil, if legumes have not been grown on the field before, it is necessary to add bacteria to the soil before planting. State agricultural experiment stations can supply the bacteria or information on where to buy them.

Save the Wildflowers!

Several institutions and organizations have turned their attention to cultivating and protecting native plants, and some have been created exclusively for that purpose. Native plants are the primary reason for the development of the North Carolina Botanical Garden, a 339-acre area of natural forests, open fields, and creeks at the southern edge of the University of North Carolina campus at Chapel Hill. The garden encourages the study, conservation, and preservation of native plants through research, the establishment and maintenance of natural habitat plantings, and the education of the public in appreciation of native flora. The garden consists of steep wooded slopes, deep ravines, rhododendron bluffs, and low pinelands. There is a cranberry bog planted with wild cranberry, bogbean, cottongrass, and white beaked rush. A coastal plain savanna and bog has been planted with the beautiful fringed orchid, pitcher plants, sundews, Venus’s-flytrap, and yellow-eyed grass. In order to duplicate the fires that occur in nature in these savannas, garden personnel conduct controlled burns during the dry periods of winter.

The New England Wild Flower Society has created Garden in the Woods, the largest landscaped collection of native plants in the northeastern United States. Located on 45 acres near Framingham, Mass., Garden in the Woods features 1500 different species in habitats that run the gamut from rich woodland groves, sunny bogs, and pine barrens to western gardens, meadows, and even a lily pond. Flowering begins in April with hepatica and trailing arbutus and continues into September and October with the blooming of wild asters and gentians
 

The American Horticultural Society’s Wildflower Rediscovery Project was created to protect endangered wildflowers. The project encourages gardeners to grow native species and provides a list of nurseries selling native plants not collected from the wild.

Long interested in wildflowers and natural beauty and increasingly concerned about the decline of some wildflower species, Lady Bird Johnson, the former First Lady, helped establish the National Wildflower Research Center on 60 acres near Austin, Texas, in 1982. The basic goals of the center are simple: to promote and to research wildflowers and other native plants. The National Wildflower Research Center calls itself a clearinghouse for questions pertaining to the native flora of the United States. During 1986, more than 24,000 inquiries were answered through this clearinghouse. To handle the explosion of interest in wildflowers, the National Wildflower Research Center has an annual operating budget of about $800,000 and permanent staff of more than 12 employees.

Several ongoing projects at the center are only a small segment of the research that is planned for the future. Current projects include evaluating commercial seed mixes on the market, studying species not now commercially available for their potential in wildflower gardens, determining the best times for planting, watering, and fertilizing different wildflowers, and studying germination requirements for a wide variety of seeds. In April 1987, Congress passed a law requiring that a portion of all federal funds for highway landscaping be used to plant wildflowers. Since that time the center has increasingly provided guidance to highway departments wishing to use wildflowers to help reduce roadside erosion as well as add to the beauty of the highways.

The Canadian Wildflower Society is working to increase public awareness and knowledge of Canada’s wild flora. The organization acts as a clearinghouse for information on the cultivation and preservation of wild flora. It encourages botanical gardens, nurseries, and horticultural schools to propagate wild flora and to provide public education programs. The society will assist members in establishing wildflower gardens and propagating native plants.

Beautifying the Highways

The beautification of roadsides is a major goal of the National Council of State Garden Clubs’ ‘Operation Wildflower.’ Working with state highway departments, garden clubs have established roadside wildflower plantings in several states. The garden clubs and their members furnish seeds, plants, expertise, and funds for the projects, while the state highway agencies determine the appropriate locations for the wildflowers and handle installation and maintenance. Landscape architects with the Illinois Department of Transportation have planted a strip of prairie soil along Interstate 57 with native prairie grasses and wildflowers. California, Massachusetts, Michigan, Ohio, Oklahoma, and Nebraska are among other states that have already been planting wildflowers alongside highways, and the practice has long been widespread in Texas. In the western United States, large expanses of roadsides are being planted with native species by a process known as hydro-seeding, where a water mixture containing seeds, fertilizers, and mulch is sprayed along the highways.

About the Author: Robert H. Mohlenbrock is distinguished professor of botany at Southern Illinois University at Carbondale. He is the author of the field guide Wildflowers (1987).


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