The only yellow flowered member of the genus Bletilla, B. ochracea, hails from south-central China. Described nearly a century ago (Schlechter, 1913) it remained essentially unknown to western garden enthusiasts until the early 1990s when plants began to circulate in the growing export trade from that country. At first it sounded too good to be true, a pure yellow flowered Bletilla species, and the lurid yellow photos that started popping up on recently created world wide web looked too good to be true. Indeed, most were over saturated to near ridiculous shades. In time plants became more distributed and the reality of this flower became less legend, and more real. Growers found themselves not with brilliant deep yellow flowered plants, but rather soft pastel ones. Nevertheless, B. ochracea remains a novelty in this genus of otherwise purple-violet flowered plants.
Bletilla ochracea is a perennial, deciduous terrestrial orchid. It’s long grass-like leaves number between 4 to 8 and grow alternately off a thick stem, with a total height of 30 to 50 centimeters. The highly pleated leaves are bright green in color, but in some clones the newly emerging growths can be suffused with dark purple-red, which turn green when fully mature. The plant looks much like a young palm tree seedling when out of flower. The thick rhizome has flattened, bulb-like internodes and a vigorous root system. Overall, the plant looks very similar to the well known Bletilla striata, but is a bit more gracile in appearance.
The flower stalk can be quite long and hold up to 10 or more flowers in robust specimens (mine never seem to have more than just a handful per stalk). The flowers bloom sequentially, and are typical sized for the genus, around 6 cm across. They have a classic “orchid flower” look, with a broad, highly ruffled lip. What makes the flower unique is its light yellow color, which can range from a pale pastel yellow to almost white. The most intensely colored part of the flower is the lip, which has a deep orange-yellow base color that is streaked with purple and red patches. The elongated, pale yellow column extends over its uppermost part, adding to the beauty of the flower. Flowering typically commences three or more weeks after Bletilla striata – in nature, from June to August.
The plant is reported to grow in a variety of habitats and elevations in south central China and northern Vietnam. It is said to be at home in both evergreen and deciduous broadleaf forest, grasslands, coniferous forest, in gullies in the shade, and thickets. Plants can be found from 300-2400 meter elevations in a wide area of China from southeast Gansu, Guangxi, Guizhou, Henan, Hubei, Hunan, southern Shaanxi, Sichuan, and Yunnan. There is a an odd and erroneous web based reference that this species is also from west Africa – something not substantiated in any literature I’ve come across.
The flowers of this species seem at least somewhat variable in color depending on the clone and also environmental conditions. Plants grown in full sun tend to have red-brown pigmentation on the sepals and petals, particularly on the dorsal surfaces. This seems to be a reaction to increased light levels. Plants in shadier areas tend to be more pale yellow. Much has been made about “red flowered” plants, as well as “alba flowered” plants. To my knowledge these are not true varieties, but rather reflect the range of genotypes (combined with environmental conditions) that exist. I’ve even seen a picture of a plant claimed to be a “pink” version – clearly not this species, but more likely a hybrid.
I have two different plants of B. ochracea – one that starts flowering early, usually a couple weeks after the bulk of my B. striata (but with lots of overlap) – and another clone that waits another couple weeks . In my area in southern Japan that translates into B. striata starting in mid May, the early clone of B. ochracea in late May, and the late clone in mid to late June. The early clone also flushes its growths a deep purple-red, while the later clone flushes green. I was told the early flowered clone is from Yunnan, but I don’t know the origin of the other plant.
A number of hybrids have been made between B. ochracea and other members of the genus, with B. Brigantes (the cross with B. striata) being one of the more famous ones (registered in1994 by R.G. & A. Evenden). I’ve grown this lovely flower which is highly reminiscent of B. ochracea except for its overall bright violet-pink color and more elongated flower segments. Not surprisingly my plant seems to commence flowering between its two parent species.
The cultivation of this plant is fairly straightforward, yet it seems to be a bit more sensitive than the more vigorous B. striata, and also a bit slower to increase in size. I have a small pot full of B. ochracea now with multiple flowering stems, but it 5 years to grow the plant to that size. A plant of B. striata ‘Murasaki Shikibu’ bought alongside it has 5 times the number of flowering stems and I’ve divided it a number of times.
Still, it can be grown similar to B. striata, from bright shade to full on sun, however in hotter climates I’d give some protection from midday sun (I do with my plants). Any good free draining compost will do, from a sandy humus to a well structured garden loam with a pH in the 5-7 range. Water well while in growth, but keep it a bit drier in winter – wet conditions in dormancy is a hazard to this plant. Drainage should remain sharp year round, even when in growth.
In terms of cold hardiness, this species is probably similar to B. striata, though a number of folks have said it is a bit more tender. Some sources indicate a hardiness range of USDA cold hardiness zones 6b-9a, though I’d expect that zones 7-8 would be more optimal. In colder areas a thick mulch in winter is advisable, and still may not be enough to carry them through. In yet colder regions growers will be forced to keep them in pots, overwintering in a frost free garage or the like. Ron Burch (The Gardens at Post Hill) digs his up in November and puts them in freezer bags in the fridge for winter.
This lovely yellow flowered Bletilla is a novel and rewarding addition to any suitable garden. Luckily nowadays they are available to growers the world over.