Pink lady's slippers vary in color from deep pink to white.  Credit: Courtesy of Aislinn Sarnacki

I came upon them accidentally. Held up by long, slender stems, the round blossoms of lady’s slippers appeared to hover over the forest floor. The large flowers ranged in color from vibrant pink to crisp white. I’d never seen so many in one spot.

That was a few years ago, in Branch Lake Public Forest in Ellsworth. This year, I returned to the forest at the beginning of June to see if the flowers still grew in such abundance. To my delight, they were easy to find.

In specific areas throughout the trail system, dozens of lady’s slippers grew on both sides of the trail. Mosquitos whined in my ears as I knelt down to photograph them.

Among the most celebrated and showy wildflowers in Maine, lady’s slippers belong to the orchid family. Their common name refers to the bulbous shape of their flowers somewhat resembling a shoe. For this reason, they’re also known as moccasin flowers.

Sunlight illuminates the flower of a pink lady’s slipper in early June in Branch Lake Public Forest in Ellsworth.  Credit: Courtesy of Aislinn Sarnacki

Maine is home to four types of lady’s slippers: pink, yellow, showy and ram’s head.

The pink lady’s slipper is the most common. Growing in wooded and semi-wooded habitats, they range in color from rich magenta to white. Some of the most striking flowers have dark pink veins threaded through pale pink pouches.

They bloom in May and June. And while they’re quite large, they’re easy to overlook. Like many other wild plants, they blend into the forest, easily lost among seas of moss and ferns. But once you spy one, you’re bound to find another, and another.

Pink lady’s slippers only grow in particular conditions. Specifically, they require a certain fungus to be present in the soil. Threads of the fungus break open the flower’s seeds, then attach to them, passing on food and nutrients. In turn, when the plant grows older, the fungus extracts nutrients from its roots. It’s a win-win relationship (also known as symbiotic).

Another fascinating thing about lady’s slippers is how they become pollinated. Their colorful flowers and sweet scent lure bees and other insects to enter their flower pouch through a front slit. Once inside, the insects don’t find any nectar to eat, but they’re trapped by hairs that point toward two exits. The insect must crawl to the exits, passing the flower’s stigma and pollen masses along the way, according to information provided online by the U.S. Forest Service.

Sometimes a trapped insect becomes so frustrated with the maze inside the flower that it chews a little hole to escape, according to the book “Naturally Curious” by Mary Holland. I’ve looked for such holes in the lady’s slippers that I’ve seen this year, but I’ve yet to find one.

Pink lady’s slippers, with the scientific name of Cypripedium acaule, vary in color from deep pink to white.  Credit: Courtesy of Aislinn Sarnacki

In the wild, a lady’s slipper plant lives an average of 20 years, and occasionally up to 150 years, according to Holland. In Maine, collecting them is discouraged. It’s also often futile.

Attempts to transplant lady’s slippers frequently fail because they require such specific conditions — including the ground fungus — to survive.  

According to the Maine Natural Areas Program, over collecting even the most common species of lady’s slippers could make them rare over a short period of time.

During my many adventures throughout the Maine wilderness, I’ve only ever seen pink lady’s slippers. I’d love to spot a yellow lady’s slipper, which is considered “uncommon” in Maine. They grow in moist, nutrient-rich forest, as well as swamps and bogs, according to the Maine Natural Areas Program. And some bloom until mid-July, so I’ll be keeping an eye out.

The showy lady’s slipper, with white petals and a pink pouch, is Maine’s largest lady’s slipper. It’s becoming increasingly rare due to overcollection and dwindling habitat. They’re found in moist environments, such as cedar swamps.

A cluster of lady’s slippers grow beside a trail in Branch Lake Public Forest in Ellsworth.  Credit: Courtesy of Aislinn Sarnacki

Lastly, the ram’s head is the state’s rarest lady’s slipper species. It has a white pouch that’s smaller than the other varieties, marked by pink-red veins. It has only been found in a few spots in Maine.

As I write this, pink lady’s slipper season is waning. Throughout June, their flowers wither, leaving behind seed pods that split and scatter seeds. Some will germinate, adding more blossoms to the forest.

Once you find a good lady’s slipper patch, you can return to it year after year and enjoy the magnificent display. They’re just one of the many wonders hidden in the Maine woods.

Aislinn Sarnacki

Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...