Iowa's Wild Orchids

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by Bill Witt

Orchids hold a special place in our view of the natural world, conjuring romantic, exotic images of bright blossoms glowing in the soft, dim light of tropical forests. But they also play a significant part in shaping our vision of Iowa's natural history: because orchids have highly specific requirements for germination, growth, and reproduction, their presence--or absence--in a woodland, bog, or prairie can provide biologists and conservationists an important clue about the quality of a natural site.

Iowa's natural heritage is rich and diverse, a "council ground of the biomes" where in pre-settlement times several of North America's great natural communities converged and overlapped. These included the eastern and northern forests, and the tall- and mid-grass prairies. In addition, rare geologic occurrences, such as the Loess Hills, the fens of northwest Iowa, and the cold air slopes of northeast Iowa's Driftless Area created micro-habitats that allowed certain species to live hundreds of miles outside their normal ranges.

Iowa’s orchids
Iowa's native orchids reflect this diversity: since 1843, when the first collections were made, until 1987 when an amateur botanist discovered the only known Iowa site for the Spring Ladies Tresses, 32 species of orchids have been recorded in The Beautiful Land. Our wild orchids range in size from the 3-inch-tall, delicately blossomed "three birds" Triphora of the eastern woodlands to the vigorous, 3-foot-tall floral spike of the Western White-fringed Prairie Orchid, Platanthera praeclara, and in colors that run from whites and pale pastels to buttery yellows and passionate pinks. Flower shapes run the gamut, too, from the chaste, tight-lipped parsimony of the Fall Coral Root (one of two saprophytic, or non-photosynthesizing, species) to the cheerful, voluptuary roundness of the Yellow Lady Slipper.

Orchids are among the most prolific of all families in the plant kingdom: over 20,000 species inhabit almost every imaginable habitat to be found between the polar ice caps, from cold, alpine regions to the deserts. Iowa's orchids, too, have matched themselves to just about every available niche, from the white oak swamps of Muscatine and Lee counties to the dry, windswept Loess Hills of Monona and Plymouth counties.

Threats to orchids
Unfortunately for our orchids, and for many of our other native species of animals and plants as well, the conversion of natural lands that has pushed Iowa's status as the most agriculturally developed state has resulted in such loss of habitat that all but a handful of orchid species are now considered threatened or endangered: six orchid species are now known to live in just one site each, and three species have likely been wiped out. For example, the showy Grass Pink orchid, Calopogon tuberosus, was last seen in 1957--on the site of a new housing development north of Cedar Rapids. The home of another beautiful species, the Purple Fringed orchid, Platanthera psycodes, was saved a few years ago from becoming a county park’s parking lot in a ""hair-of-its-roots" last-minute rescue, after hundreds of plants were found blooming just a few weeks before the bulldozers were to start work.

In subtler fashion, the clear-cutting of a mature oak forest can eliminate or drastically suppress the Puttyroot Orchid, Aplectrum hyemale. The puttyroot's life cycle is keyed on photosynthesis occurring after the forest canopy begins to open up in the fall: as other forest plants grow dormant, the puttyroot puts out its broad, cold-resistant basal leaves and starts manufacturing the next year's food supply, which it stores in its roots.

Disturbance, on the hand, can help other orchid species. A woodland favorite is the Showy Orchis, Galearis spectabilis, which is often found at the edges of trails, where there is more light and slight to moderate disturbance of the soil. Showy Orchis can often be found in logged-over woods, a few years after young trees have begun to establish a broken canopy. As the recovering forest continues to mature, Showy Orchis may decline, to be succeeded by Woodland Twayblade, Liparis lilifolia, which will itself decline as the canopy closes over.

Other agents are posing increasing threats to woodland orchids and their neighbors in high-quality natural habitats. Two of the most destructive are white tail deer and the aggressive, alien garlic mustard, whose seeds deer may help spread. At one state park, the largest known population of Fall Coral Root orchids (over 500 plants) was virtually eliminated by a deer herd that sheltered at the orchid site during successive annual hunting seasons and grazed the forest understory to bare ground. Garlic mustard, on the other hand, produces great quantities of seed that deer herds may help spread. Garlic mustard is rapidly taking over thousands of acres of forest floor in eastern and central Iowa, crowding out the native plants while ironically remaining untouched by deer that seem to like to eat almost everything else.

Iowa's wetland and prairie orchids have been hit hardest overall by habitat destruction because of conversion to cropland. Woodland orchid species were assumed until recently to be at least reasonably safe from elimination, as long as logged areas were replanted or allowed to regenerate naturally as forest.
If Iowans don’t work together to protect our orchids and other native species, we may soon be seeing almost all our native orchid species on the "threatened and endangered" lists. And Iowa will lose a little more of its romance.

Bill Witt is a freelance writer and photographer from Cedar Falls. He also serves in Iowa’s House of Representatives.

Check out these orchid resources
Central Iowa Orchid Society's list of Iowa native orchid species

A list of endangered and threatened species, federal and state

Iowa Department of Transportation's Enviro-Explorers Kids Club has descriptions of several Iowa-threatened species, including some orchids

An extensive list of orchid books--mostly for gardeners

For more information about this story or other Foundation news, e-mail Cathy Engstrom, Director of Communications, or call (515) 288-1846.