By Kevin Allen
Few plants can match the allure of an orchid. As one of the largest and most diverse plant families, the Orchidaceae currently boasts about 30,000 identified species. They grow on every continent except Antarctica and can be found in the tops of trees, on the sides of cliffs, in floating mats of aquatic vegetation, and in the soil beneath our feet. More than 60 orchids are native to the Mid-Atlantic region, and several can be found in the gardens at Mt. Cuba Center.
Image 1: White grass-pink (Calopogon tuberosus “white”)
For greenhouse assistant Stephen Pyne, propagating and growing these native orchids has been a fascinating journey. “Like everything, it’s a spiral,” Pyne says. “I first came to orchids probably in my twenties with the fancy, beautiful, tropical orchids, and then I sort of lost interest.” Pyne’s focus then shifted for a while to ferns, clubmosses and spikemosses – until he learned something peculiar. One of the life cycle phases of these plants is called the gametophyte, and in some species it relies on fungi as its source of nutrition. “Clubmosses in particular have a non-photosynthetic gametophyte, so they parasitize fungus just like orchids parasitize fungus,” Pyne says. “And so that led me back to the native orchids. They grow in similar environments, and they also parasitize fungus to grow from a germinating seed to a photosynthesizing plant.”
Image 2: Rose pogonia (Pogonia ophioglossoides)
While the complex ecology of these plants is indeed fascinating, it can pose a problem. Orchids’ symbiotic relationships with fungi can make them difficult or impossible to grow in a garden setting. Fortunately, some native orchids are more adaptable than others. Perhaps the easiest to grow is Chadds Ford Atlantic ladies’-tresses (Spiranthes bightensis ‘Chadds Ford’), which produces spirals of fragrant white flowers in the fall. Pyne says it is a very good generalist garden orchid that does well in pot culture or a moist woodland environment. It can also take more sun if it has more moisture, in a bog garden container, for example. It even pairs nicely with native carnivorous pitcher plants (Sarracenia spp.). “Spiranthes is definitely one of the orchids that is a little bit more promiscuous,” Pyne says. “It will seed itself around. It never outcompetes other plants, but it does show up in other pots.” Although it is easy to grow, Pyne says he has had trouble with squirrels in his yard eating its fleshy roots and leaves.
Image 3: Chadds Ford Atlantic ladies’-tresses (Spiranthes cernua ‘Chadds Ford’)
Other orchids that are well-suited to perennial bog garden containers include grass-pink (Calopogon tuberosus), white fringed orchid (Platanthera blephariglottis), yellow fringed orchid (Platanthera ciliaris), and rose pogonia (Pogonia ophioglossoides). All of these are summer-blooming orchids that can be grown with pitcher plants, sundews (Drosera spp.), and other carnivorous plants in a mixture of half sand and half peat moss. They require moist, acidic conditions and need water that lacks dissolved minerals. Rainwater is the best source. Pyne says these bog orchids can be purchased online from reputable mail-order carnivorous plant nurseries.
Other commercially available native orchids that can be more challenging to establish in the woodland garden include large yellow lady’s slipper (Cypripedium parviflorum var. pubescens) and Kentucky lady’s slipper (Cypripedium kentuckiense), with the latter being a bit easier. They have yellow pouch-like flowers that bloom in spring. Nearly 100 of these orchids were planted in Mt. Cuba’s newest garden addition, the Woodland Glade, in 2021. With a fallen willow oak anchoring the bed, the Kentucky lady’s slippers are dotted throughout a sea of Virginia spring-beauty (Claytonia virginica) and marginal wood-fern (Dryopteris marginalis). Susan Boss, Senior Horticulturist in the Entrance Garden, says these orchids must be handled carefully and planted in a location that suits them well. “We had to be delicate and take our time, kind of like with trilliums,” Boss says. “Really, it’s about putting them initially in the right spot.”
Image 4: Kentucky lady’s slippers (Cypripedium kentuckiense)
Kentucky lady’s slippers and large yellow lady’s slippers prefer moist, well-drained, slightly alkaline soil in part shade. A handful of crushed oyster shells can be added to the soil as a source of slow-release lime. In the right conditions, they form multi-stemmed clumps over time. Signs of stress in these plants include scorched leaves and off-green leaf coloration. Boss says this can be caused by too much sun exposure, which will require some of the lady’s slippers in the Woodland Glade to be transplanted to shadier spots this spring. Because of the delicate nature and tricky growing conditions of the lady’s slippers, Pyne would recommend them only for more advanced gardeners. For anyone interested in learning more about growing native orchids, there are a variety of online discussion groups. For conservation-minded individuals, the Native Orchid Conference is a nonprofit organization that hosts an annual symposium with field trips to see the orchids in situ. “It’s a rabbit hole,” Pyne says, “and you can really go down deep.”
Image 5: Large yellow lady’s slippers (Cypripedium parviflorum var. pubescens)