den aggregatum (lindleyi) missed winter rest?
 

I have a den aggregatum var. majus (which I understand to be a den lindleyi, I think). In SW Michigan I grew it outside during the summer & it thrived. I brought it in late Fall & frankly I suspect I missed the winter rest. At this point, the plant has started putting out new roots (almost 2 weeks ago) & I noticed this morning that it is beginning a new pseudobulb growth. What I'm looking for at the moment is: Is this the evidence that I'm not going to get any spikes/blooms this year? And do I start watering/feeding again now? I have a "plan" to be better organized about this winter rest next year, but am wondering what to do now.

I took a look at mine. I have given it a Winter rest, watering roughly once a month for the last 4-5 months and high temps of around 60f. I noticed new root growth only - which means no spiking or bulb growth. I had been advised that these should be returned to normal watering and temps in early March. So time will tell. These are otherwise known as Den Aggravation because they are hard to rebloom.

Thanks for the input - I left the plant outside in the Fall pretty "late" I thought (close to November, weather allowed for it)....It had a very bright spot indoors after that, but I don't think I kept it cool enough, & I believe I made the mistake of watering/feeding it a couple more times after I brought it in - in part because the new PB it developed was still growing. I thought I needed to keep feeding it. When that PB matured, I stopped with the watering/feeding, but at that point maybe it was all too late. Hurumph.

Withholding fertilizer early, plus cool temperatures, seem to be the two most important factors for winter-dormant Dens. Cool means too cold at night for most people's living spaces.

Again - the input is so helpful. So now I've collected a couple of things that "went wrong". (1)Withholding fertilizer early: this plant grew a lovely PB that promptly lost a leaf late summer & then started a new PB. Because it started the new growth, I kept feeding/watering. (2)Cool temps: I left it outside until roughly November - but I kept feeding/watering due to the new growth. (3)Light - when I finally brought it inside, I don't think it had enough supplemental light AND I continued the watering/feeding for a few more weeks. (4)Back to temps: I wonder if I'd left it outside in the Fall WITHOUT the water/feeding if things would have worked out. Because it would have been cool & bright. But in my house, there's no place it's going to be below 60F, let alone 50F, unless it's in the garage, & there it wouldn't have enough light, unless I used supplemental light. Tricky!

I don't know how cool is correct.

I went to a talk by Winn Winmaw about his native Burma, specifically the northeast Shan Plateau. Burma stretches from 9 degrees north to 29 degrees north; this plateau is not entirely in the tropics. There, in the mountains, grows Dendrobium chrysotoxum, a relative of Den. aggregatum. The books say there is no rain there in the winter, and that is true, but Winn says there is so much dew every single night that the ground is constantly wet and slippery. It is also extremely windy most nights, to the point Winn said it is difficult to stand up in the wind on the slippery wet soil. Temperatures are just a little above freezing, but never freezing. The orchids grow on trees, completely wet and cold all night long, for the entire winter. They flower spectacularly in spring.

Vanda coerulea grows close to here, as well. It is lower in elevation and not so wet, but almost as cold at night.

My basement has high humidity and is much cooler. Temps max at 60f but have fallen to 48f. That said we'll see if that made much difference. I've brought my Den. Aggravation upstairs to a windowsill and min temps of around 70f.

Is den. ejerii at all related to the lindleyi? I have an ejerii which looks really similar to the lindleyi but maybe they have nothing to do with each other; if so please ignore the following. I grew the ejerii outside this past summer, brought it inside in Oct, and never stopped watering it almost every day (it's mounted on a stick). It's putting out 9 spikes right now on the 6 pbulbs it developed last spring. It sits in a SE window and it's in a room that doesn't get below 59F. If this wanted a dry winter rest it didn't tell me. It also hasn't stopped growing new roots all year.

I had the same orchid for over five years. And NEVER once got it to bloom again. But have never heard of Den. Aggravation before. :rofl: I spit my drink when I read this.

I solved my issue by pitching it. It made me feel better. That'll teach Den Aggravation to over-agitate old people!
:biggrin: