Dendrobium victoriae-reginae -- rapidly yellowing leaves and leaf drop
 

Hi all,

I have been keeping a D. victoriae-reginae until recently. For about 1 year it was living in on a tinted windowsill in a moss-bark mix, watered just when moss became crispy. The plant seemed healthy for most of that year, sent up 2 new canes and flowered twice.

Unexpectedly, the bottom leaves of 1 cane turned a mottled yellow over the course of a day, and dropped the next. Over the course of about a week, this moved up to the top of a cane, and began with the next. At the point when all mature canes were toasted, I plucked a seemingly unaffected keiki and have tried keeping that one alive, but it too is now doing the same thing. Picture attached shows how the yellow mottling looked.

I don't believe the media had been too wet as it was allowed to reach "just about" dryness between every watering, and the size of the pot was not so large that I woulr have expected a wet core.

Any indications what this is? If this keiki can be saved that would be great news, but I would be happy to know what caused this and how to prevent in the future. Best,

First, Welcome!

That Dendrobium looks very much alive (firm canes) It's semi-deciduous, and can bloom on the same leafless cane for several years. So, I think just force of nature (aging canes dropping leaves). (I don't consider a Dendrobium dead until it is shriveled and hasn't done anything for a year... it is amazing to see flowers pop out of what looks like a lifeless stick!)

My Den victoria-reginae tends to have one or two new canes with leaves, the rest are bare, and that's where the flowers some from.

If the window is tinted, it may be filtering out some wavelengths of light that the plant wants. I'd suggest trying it in a place where it can get more natural light if I understand your statement about the window correctly. I have found that it does do better with RO water if you have that available.

Suggestion... if you get more keikis, don't rush to remove them. They aren't draining the plant - they have roots and leaves, so they can contribute. And they then become yet another source for flowers.

Look for spider mites under the leaves. They cause lots of problems indoors on thin-leaved orchids in less than ideal humidity.