Mushy yellowing oncidium
 

Hi everyone. My mounted Oncidium twinkle has always been amazing - I've had her for about 3 years, and no problems. I moved a few months ago and it's been problem after problem with my orchids - my Oncidium was ok for ages, and past few weeks more and more pseudobulbs seem to be somewhere between mushy and dried out, leaves yellowing and drying. My dendrobium seems to have done something similar recently as well. It seemed to be all on one side of the mount, with the side toward the window doing better, so I moved her around, but I am not convinced light was the problem. Does anyone have any ideas?

It's not getting enough water. They shouldn't dry out. I would not be able to keep a small thirsty plant like Twinkle alive on a mount.

Hello Rowena:
I bought my Twinkle over 8 years ago and it was potted in sphagnum. Twinkles are wonderful to have around when in bloom.
I continue to re-pot in sphag whenever I pot up to a new size pot, or do divisions. (you can't have too many Twinkles) It's been very successful. Only in a couple of cases of very small divisions has it not worked. The last boo-boo being that one division either got too wet and/or cold causing a pseudobulb to rot.
The mother plant and other divisions on sphag are fine.

You could try wrapping sphag around your current mount and keeping it moister, ro cut the wood mount so that the plant's roots are still clinging to the remaining wood, then pot in sphag.

Just a suggestion, and I wish you best of luck.
Maryanne