Black spots on Dendrobium spectabile leaves and cane

[avisignis36@gmail.com]

Help! My den spectabile seems to have a bacterial or fungal infection. It has numerous black spots on the leaves. It seems like they have increased in number (but not size) over the past few weeks. None of the leaves have turned yellow or brown or wilted, and the roots seem to be continuing to grow well. Most concerning I think is the black depressed ring around the youngest cane. What should I do - do I need to cut away all areas that seem diseased?

[camille1585]

It's not unusual for Dens to get all sorts of spots, often it's due to lack of air flow, when grown inside. But it seems that you grow yours outside? Not sure about the black ring on the cane, I don't grow many Dens...

[avisignis36@gmail.com]

I just recently put it outside. Before, I had it inside near a window in a room with a constant fan to move air. I have recently had several plants that clearly did have some kind of rot on their leaves, and the most affected one was my den kingianum. I've been pretty aggressive with cleaning and cutting back anything that looks like rot, and it seems fairly under control at this point. But the spectabile just looks different, and the leaves don't seem to be suffering or dying (the spots have been there for a while). So I don't know if it's related, and I'm mostly concerned with the blackness on the cane.

[Dollythehun]

Mine did the same thing. My opinion was it was due to my irregular care. I just gave it away, with bud nubbins and all. No room.

[rbarata]

I wouldn't worry about that. At least in my case I consider it normal.

[Roberta]

As far as the dark area on the cane, just keep an eye on it. If it starts to feel soft and spongy and spreads, then it may need amputating, but don't rush to cut. Cutting is permanent, and if you make a mistake you can't put it back. Don't worry about the black spots on the leaves, I see no sign of anything to worry about there. just observe.

[legion80]

I had the same concern regarding spots on my leaves. It did not spread, and might have simply been sunburn. I have since moved it to a place slightly less direct, and all new growths have been fine.

My problem is that I've only been getting canes, and no flowers! My den has at least two dozen of them, and they're still going. I haven't figured out how to encourage flowering.

[Roberta]

Spectabilie tends to get very large. San Francisco? A challenge to give enough light and warmth to make it happy.

[Dollythehun]

They have to be very large to bloom. Here in the Midwest, mine required full sun. This may require you supplement your lighting. They prefer lots of food and water during the growing season and little food in the winter season. But still high light and slightly decreased water.