People who don’t grow orchids often consider them to be difficult. People who do grow orchids sometimes feel the same way about terrestrial orchids, particularly hardy species. Your average orchid grower is perfectly happy messing around with ultrasonic humidifiers, high tech fertilizers, and complex potting mixes containing exotic and expensive materials, both organic and inorganic, in an attempt to grow a delicate little epiphyte from Borneo or the Peruvian cloud forest. But give them an orchid that grows in the ground outside, and they are at a loss.
Bletilla striata, the Chinese ground orchid, is one species that defies the expectations of both orchid growers and those who just admire orchids from afar. It’s a terrestrial orchid that is very easy to grow, and given a modicum of care it will steadily increase in size until you have a huge clump to impress your friends. If you can grow a daffodil, you can probably grow Bletilla.
According to IOSPE, Bletilla striata is native to China, Korea, and Japan (people in the latter nation might have something to say about calling it the Chinese ground orchid). I’m not sure where in its fairly wide native range the plants in cultivation originate, but they are certainly cold hardy. My plant has easily survived 5 F (-15 C), and the species is reported to be hardy in USDA Zone 5 (-10 to -20 F, -23 to -29 C winter minimum) with protection. My plant is growing in my standard mix of native clay and permatill, top-dressed with hardwood mulch, but any reasonably well-drained, slightly acidic garden soil would probably be fine. Morning sun and some afternoon shade will provide sufficient light for flowering without scorching the leaves.
The flowers are relatively short-lived and don’t have the greatest form, but the buds open successively for several weeks. In addition to the standard pink form, there are alba (white-flowered) and coerulea (“blue”) forms. Several clones with variegated leaves are also widely distributed. This spring, I obtained several pseudobulbs of an alba clone at a very reasonable price from one of the big bulb vendors. I’ll be interested to see if it grows as easily as the typical form.
If Bletilla striata has a flaw, it is its eagerness to grow in early spring, at least in our mild climate. The pseudobulbs are fairly close to the soil surface, so they warm up quickly and often initiate new growth in February, long before the last freezing weather. Although dormant plants are very cold hardy, the new leaves, and especially the flower buds which emerge simultaneously with the leaves, are very sensitive to frost. Leaves will continue growing even if the tips freeze, but frozen buds mean no flowers until next year.
This past winter, we had very warm weather in February, and new growth was well under way when a low of 25 F (-4 C) was forecast. In an effort to save inflorescences that were already starting to emerge, I covered the entire clump with a black plastic cement mixing tub and several inches of mulch. I keep several of these sturdy tubs around to serve as water reservoirs for potted bog plants, and they are also very useful for covering tender plants. After several days, I removed the tub so that the new growth wouldn’t rot in the humid darkness and then replaced it again when more freezing weather was forecast. The procedure was labor intensive but worked perfectly, and this year’s display of flowers is probably the best yet.
In my post about Calanthe sieboldii, I mentioned that the hybrid Calanthe Takane was in bud. The flowers are now open, and I am quite pleased. C. Takane is a cross of C. sieboldii and the much smaller and less colorful, but hardier, C. discolor. My C. Takane shows its parentage in the yellow lip (from C. sieboldii) and reddish brown sepals and petals (from C. discolor). It is intermediate in size between its two parents. Take a look: