Dendrobium hekouense

[Fredmax]

I've recently purchased one of these mounted with sphag, and out of the dozen plants from the seller this one has struggled the most. I've moved it from a bright hot humid greenhouse to a shadier warm humid one, and now a bright spot in a terrarium with paphs. It just keeps going downhill and yellowing leaves then losing them. Is there something specific I should be doing with this different to most other orchids? It has been quite warm in recent weeks.

[Roberta]

The heat may have been the culprit - these are relatively high-elevation plants. (1000-2000 m in Yunnan, China) My only suggestion would be to increase watering. Also... it is a bit early to be losing leaves, but these do. I don't particularly dry my in winter and it does fine - but it definitely is deciduous. It's approaching the time of year when it even could be "thinking" of blooming. It blooms when it is pretty leafless. But do what you can to cool it off.

[Fredmax]

Thanks Roberta, do you know if it has high humidity needs like a lot of Dens. I'm considering moving it to a shadehouse near my Soph coccinea. I checked with the seller and he grew it outdoors (albeit in a more tropical climate). I've grown it in 60-75% humidity so far but outdoors will drop it down to around to 30% and in my experience often gives poor results with mounted Dens (other than aussie ones).

[Roberta]

Mine gets whatever humidity happens in my yard. Summers tend to be around 40% in the middle of the day (higher at night of course) There are periods (usually for just a few days) any time of year when the humidity goes down to single digits and the hot winds blow. So I don't think it's fussy. Conditions that work for S. coccinea should be quite good. Both will tolerate heat, do it better if it cools off at night. But I suspect that my climate is less humid than yours, doesn't seem to matter for the orchids - if it's dry, I just water more.