Orchids in Appalachia

Spring begins the transformation of our southern Appalachians from the Canada-like sparseness of winter to the verdant, vibrant feel of the tropics. Each hillside, tree, and leaf is a variation on the theme of green—chartreuse, lime, emerald, jade, and olive. The recent rains accentuate the moist tropical profusion of life in our own forests, as flowers and fiddleheads open and unfurl.

Perhaps nowhere is the similarity to the tropics more complete than in one group of plants, the orchids. Seemingly overnight, globes of yellow or pink atop slender stems erupt from the forest floor as lady’s slipper orchids nod their heads to the advances of bumblebees, acquiescing to their insistent intrusions. A hovering bee bumps into a flower’s hollow slipper, or moccasin, slips through the open cleft of the pouch-like lip, and is trapped inside. Unable to exit by its entry route, the bee climbs upward toward the flower’s hood, fumbling through the tight furrow formed by the fusion of flower parts, first passing the female stigma and then brushing against the male pollen sacs before finding the escape opening. This tight embrace ensures the bee is unwittingly covered with orchid pollen. Entranced by another pink slipper, the bumblebee repeats his performance, this time depositing his pollen baggage on the new flower’s stigma, thus fertilizing the flower and allowing it to set seed. Again, the freed bee seeks another flower and the cycle is repeated.

The orchid is elaborately designed to use the bee for its own reproduction, but what benefit, if any, accrues to the bee? Some flowers provide nectar that only their pollinator can reach. Other flowers are less forthcoming, providing nothing in return for the bee’s efforts. Unmoved, these alluring flowers rely on the naivete of the bee, enticing it time and again into delivering the flower’s future progeny.

One reason that there are so many different species of orchid – and there are more kinds of orchids than any other family of plants -- is precisely because of their dependence on insects for pollination. From the orchid’s point of view, only one kind of insect should deliver its pollen and that insect should be loyal to one species of orchid alone. That way, the orchid will receive only its own species’ pollen and not pollen from any other kind of plant. Most orchids are extravagantly designed to lure but one kind of pollinator: one species of orchid for each species of insect. Remembering that there are more species of insects than all other animals put together, it comes as no surprise that the orchids are the most diverse family of plants.

Why are orchids such interesting flowers? It isn’t simply the beautiful colors, because even the tiny white flowers are interesting. Perhaps it is their complexity. With a little imagination, orchid flowers resemble animals. After all, they are designed to attract animals. If seen from an appropriate angle, the flowers of lady’s slippers look like hummingbirds or hawkmoths pollinating a different flower. The cranefly orchid is another great example—each flower looks something like a fly and is, in fact, pollinated by flies! Butterflies visit yellow-fringed orchids and leave with pollen stuck to their heads. Perhaps, like the insects, we are tricked into seeing something other than a flower, and that is what we find so irresistible about them.

There is a progression of orchid species that bloom until fall. In addition to the moccasin flowers, showy orchids and puttyroot are blooming now. Green woodland orchids and green adder’s mouths come next, then cranefly orchids and rattlesnake plantains. Late season yellow-fringed orchids are followed by slender ladies’ tresses, which may bloom even until frost appears again. In addition to these common species, we have many other uncommon ones as well. Most pollinators are known, but some are not. Take notes or a picture and let me know if you find a pollinator on an orchid!

Like the tropics, we abound in orchid species, but ours are terrestrial and deciduous, storing energy collected by their transient leaves in roots protected by the warmth of the soil from winter’s cold. By contrast, most tropical orchids are evergreen epiphytes, growing high in the canopy of trees where their leaves are exposed to sunlight, but their roots cannot reach the soil. Decaying tree leaves and mosses collect around the orchid roots, and nutrients are released as abundant rainfall extracts them. Their leathery, strap-like leaves are present year round to absorb the diffuse tropical sunlight and are in no danger of freezing.

By the way, terrestrial orchids rarely transplant successfully because they enjoy another complex relationship, this one with a fungus. The fungal fibers in the soil enter the roots of the orchid to supply it with food, and if the fungus dies, as often happens when orchids are dug, the plant essentially starves to death. Enjoy the orchids where you find them, but don’t try to move them unless you are prepared to move a wheelbarrow’s worth of soil as well.

Photos by Ed Ruppert: Bumblebee pollinating a pink lady’s slipper.

Text and photos may not be used without the author's permission