Need help with discoloration on dendro. canes!
 

Good morning, all.

I posted a thread in the beginner's forum inquiring about this, but nobody seemed to have any idea. I bought my first dendrobium a little less than a week ago and I have noticed that the stalk under the top leaves is turning dark green with a yellow neck. The canes are very rigid and firm, even where the discoloration is.

The dendrobium is named Valley Isle Blue 'Blue'. The bottom most leaf on the tallest cane is coming off and it looks as though the bottom most on the smaller cane is also. The smaller cane has the same discoloration. Also, there was a small nub inbetween the leaves on the smaller cane and it is yellow, though it used to be green.

I repotted it yesterday in chc/bark/charcoal/peat mixture, its roots looked good, only a couple were dead. It was overpotted and in sphag when I got it.

Any help on identifying this issue would be helpful, I am new to dendrobiums and I am not sure if this is normal or not.

Could be normal leaf dying, or could be from cold - tho I would expect more leaves to be affected if the cause was cold, or some other problem.

Yellowed nub may have been a spike or keiki nub that aborted.

The canes are covered in sheathy material, that will yellow with age, and eventually become brown and papery and slough off with time.

But what about the dark green/yellow under the leaves on the cane? =\ That is the most concerning thing for me at the moment.