In climates where they are winter hardy, is the best hardy orchid to start with because they are very adaptable to a wide range of environments. The genus contains 8 species that are native to Asia. Three species, the pink flowered Bletilla formosana, the yellow flowered Bletilla ochracea and rose-purple flowered Bletilla striata are common in horticulture. Mature bletilla form a series of inflorescences (racemes) for up to 10 weeks in the spring or early summer. Each inflorescence arises at the tip of a stem and has three to ten, 1.5- wide, nodding florets.
Bletilla also have shallowly pleated (plicate), narrow deciduous leaves that are attractive even when the plant is not in flower. The plants are deciduous and grow to about 1.5′ tall. In their native environment, they grow in dappled shade under a canopy of tall grasses but they adapt well to a wide range of woodland sites. In the garden, bletilla prefer evenly moist, well-drained soils and a position in half-day sun or light shade. Bletilla are fairly drought tolerant, but the growth rate slows dramatically when they aren’t kept moist. When they growing well, they quickly form large clumps.
At the northern end of their hardiness range bletilla need a winter covering of mulch to protect the roots. At the southern end of their range they may emerge early, during warm spells, and are thus susceptible to late freezes, so when possible, plant them in a cooler spot in your garden where that can help to delay their spring emergence.
The name Bletilla literally means -little Bletia’ which is a New World orchid genus that it resembles. In turn, Bletia is named for a Spanish botanist and apothecary Don Luis Blet. Bletilla goes by the common name Ground Orchid. There are over 40 cultivars and hybrids of Bletilla that have been selected for flower color or variegated leaves. Breeders are focusing on increasing flower size, increasing the number of florets per inflorescence, creating plants with more outward facing flowers, and improving the color of the white flowered forms.
The foremost breeder of Bletilla is Richard Evenden of Spalding, United Kingdom. He is responsible for most of the hybrids. Other prominent breeders include Dr. William Mathis of Wild Orchid Co. of Carversville, Pennsylvania and Jewell Orchids of Colbert, Georgia. Several Japanese cultivars have been imported to the U.S. market and are becoming more widely available.
Bletilla formosana (Taiwan Ground Orchid) Bletilla formosana hails from Taiwan, Japan’s Ryuku Islands, and the Chinese provinces of Gansu, Guangxi, Guizhou, Jiangxi, Shaanxi, Xizang, and Yunnan from 2000′ – 9500′ elevation in grasslands and evergreen forests. The linear green leaves are topped in late spring and early summer with 18-24- tall flower spikes, ending in 1-6 pale pink flowers. Most of the Bletilla formosana in commerce isn’t particularly winter hardy, but based on its natural range, there are certainly some high elevation forms that should be much more hardy. (Hardiness Zone 8-10, at least)
Bletilla ochracea (Golden Chinese Ground Orchid) Bletilla ochracea hails from evergreen forests and grasslands from 1000′ – 7500′ elevation in the Vietnam and the Chinese provinces of Gansu, Guangxi, Guizhou, Henan, Hubei, Hunan, Shaanxi, Sichuan, and Yunnan. Similar to the more common Bletilla striata, these counterparts are a bit more finicky in the garden. Growing much slower than relatives, Bletilla ochracea prefers a moist woodland soil. In spring, the stalk bearing two long, pleated green leaves emerges from the underground pseudobulb. In early-to-mid May in NC, the clumps are topped with 18- tall stalks of 1″ light yellow flowers with a lip that can range from light lavender to dark yellow. I have read reports of Zone 5 hardiness, but have yet to see confirmed temperature data of plants withstanding -20F without snow cover. (Hardiness Zone 7b-8)
Bletilla ochracea ‘Chinese Butterfly’ Strain (Chinese Butterfly Ground Orchid) Although not as winter hardy as its cousin Bletilla striata, it more than makes up for this with its stunning jewel-like flowers. The 20″ wispy flower stalks emerge from below-ground pseudobulbs, and top the iris-like pleated leaves in June. Each flower stalk is topped with 3-5 small, creamy yellow flowers, each highlighted with a purple and yellow speckled lip. Bletilla ochracea is a slow grower, more finicky than Bletilla striata…moist rich soil and morning sun or high filtered light shade are best. This Linda Guy introduction is from Sichuan, China. (Hardiness Zone 7b-8 at least)
Bletilla striata (Chinese Ground Orchid) is a large group and is covered under a separate article in this series on Hardy Orchids.
Bletilla szetschuanica and Bletilla yunnanensis are two species that are now theorized according to the Flora of China to be natural hybrids of Bletilla formosana and Bletilla ochracea.
Bletilla hybrids are a large and complex group and are covered under another article in this Bletilla series. Gardeners interested in hardy orchids should start with Bletilla ochracea because it is by far the easiest hardy orchid to grow.