Bletilla Rchb.f. is a genus in the Orchidaceae family. Its native range spans from Tibet in the west throughout China, Taiwan, Korea and Japan, as well as reaching the northern parts of Thailand, Myanmar and Vietnam. The species most often grown is Bletilla striata. Although it is an orchid with delicate-looking flowers, Bletilla striata is a reliable and undemanding plant when grown in a pot.
Like with many other widespread genera there has been some confusion about the number of species. Currently, PlantsOfTheWorldOnline accepts six species, but classifies B. szechuanica and B. yuannensis as synonyms of B. formosana, though both have been utilized in RHS-registered grexes.
Bletilla ochracea is native to Yunnan and Sichuan provinces, China. It is the only yellow Bletilla. It grows well in full sun in the Bay Area where it gets natural rain in the winter and artificial watering during the summer. Plants produce a corm-like resting structure. Photo 1 was taken by Alberto Grossi and photos 2-4 were taken by Nhu Nguyen at the UC Botanical Garden.
Bletilla striata is a terrestrial orchid from China, Taiwan and Japan. The rhizomes will form pseudobulbs half in and half out of the soil from which the leaves and flower stems appear early in the year. It has lance like, ribbed, mid-green leaves and bears bright purple-pink flowers between April and July. Plant in leafy, moist but well-drained soil in light shade in a sheltered site. Needs to be on the dry side in winter when dormant. May need a winter mulch in regions that get regular frosts and can also be planted with the pseudobulbs completely underground to improve hardiness. Pot grown, first two photos by Arnold Trachtenberg. Third photo is by Michael Mace, who grows them in California in a pot with good drainage and year-round water. This photo shows the very pronounced ruffles in the throat of the flower. Fourth photo by David Pilling.
I planted the pseudobulbs about four years ago in a border. In winter (I live in the North of Italy and we usually experience -10/-15 °C) I mulch them with dried leaves. I noted that it is frost resistant, but it is very sensitive to late frost. All photos below by Alberto Grossi
Bletilla striata var. alba is not so vigorous as the former. The white flowers get a purplish tinge with age. Pictures by Alberto Grossi and Martin Bohnet
Bletilla striata var. albostriata has delicately white edged leaves.
Bletilla striata 'Soryu', which has blue flowers; photographs by Mari Kitama and Martin Bohnet; Soryu means Blue Dragon.
Bletilla striata 'Tri-Lips' has a very peculiar flower mutation, forming ruffled lip structures from all three inner petals.
Most of the registered hybrids in Bletilla have been created by Richard Evenden and are recognizable by their name starting with "Penway". There are however a few unregistered clones and forms from other sources availyble.
Bletilla 'Dark Red' is a not RHS-registered hybrid or selection which is especially advertised for expanding the Bletilla color range towards red. As it is common with "red" crossings in families containing magenta and yellow base colors, the red impression seems to be limited to certain conditions and lighting situations. For Martin Bohnet magenta seemed to be the dominant color; only the buds showed a clear burgundy red coloration.
Bletilla 'Penway Paris' is a primary hybrid of B. striata and B. szechuanica registered by Evenden in 1994, but in case the synonymy of B. szechuanica as B. formosana is verified, this would be overridden by the grex name 'Yokohama', registered by Suzuki in 1956. It's a pale pink Bletilla, with purple marks on the yellow lip.