I have a Bletilla striata orchid, which is a hardy orchid, the tag says hardy to -23C. I have a glass greenhouse where the ground inside never freezes in the winter. Do you think the orchid would survive if I planted it in the ground in the greenhouse? Thanks, John
Thank you for contacting Toronto Master Gardeners regarding the winter care of your Bletilla striata orchid.
Bletilla striata, the hardiest of the terrestrial orchid species, is known by several common names such as hyacinth orchid, urn orchid, hyacinth bletilla, hardy orchid and Chinese ground orchid. It is native to China and Japan. Unlike epiphytic orchids which are “air” plants that grow on supports such as trees, terrestrial orchids grow in part shade in well-drained medium moisture soil. Your growing zone is not mentioned, but the information on the plant tag indicates that it is hardy to Canada Plant Hardiness Zone 6.
While it has been known to survive outdoor winter temperatures as low as those of zone 5 when well mulched, a cool greenhouse where the ground does not freeze would be suitable and protect it from winter weather extremes. As this orchid requires a dormant period to bloom well, it would be reasonable to pot it up in a mixture of 2 parts peat to 1 part sand. Potting will make it easier to plant it in the garden in spring. If you wish, you may sink the pot into the soil of your greenhouse or just place the pot in a greenhouse area where the winter temperature does not rise above 4-5⁰C. As the plant becomes dormant, the leaves will fall. It needs a cool dry rest but not be allowed to try out completely. Carefully increase the watering once new shoots appear in early spring.
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Enjoy your Bletilla striata orchid.