Winter rest for mounted orchids

[Roberta]

Originally Posted by Nicolasdperez

Thank you so much for your info, but I have some questions:

1) drought, not temperature change, is responsible for flowering in den aggreg?

2) I recently got some den nobiles in bloom, so in order to rebloom them next year I should lay off watering around October?

3) I gave my den aggreg fertilizer twice and watered normally since sept 15th…. Does that rlly mean no blooms for me this year?

1. if you ask 5 people, you may get 8 opinions. It's nickname is Den. "aggravatum". Since everybody's conditions are different, there' are likely to be several "right" answers.

2. If your Den. nobile hybrid is in bloom now, it has been hybridized with other species and hybrids that likely have less need for winter rest than the species Den. nobile. That being said, the advice of "no water from Halloween to Valentine's Day" is a good way to kill the plant... I learned that the hard way, it may work in Hawaii or south Florida with high humidity, at my house it is far too severe. I'll reduce the frequency of watering but not eliminate it.

3. You'll find out next spring.

[Nicolasdperez]

I see, thank you both. That works for me because i have reduced watering from everyday to twice a week for my den agregg. So then we are responsible for changing the conditions and inducing dormancy? It’s not the plant that goes dormant and then we change our conditions accordingly?

---------- Post added at 10:04 AM ---------- Previous post was at 09:59 AM ----------

Originally Posted by Roberta

1. if you ask 5 people, you may get 8 opinions. It's nickname is Den. "aggravatum". Since everybody's conditions are different, there' are likely to be several "right" answers.

2. If your Den. nobile hybrid is in bloom now, it has been hybridized with other species and hybrids that likely have less need for winter rest than the species Den. nobile. That being said, the advice of "no water from Halloween to Valentine's Day" is a good way to kill the plant... I learned that the hard way, it may work in Hawaii or south Florida with high humidity, at my house it is far too severe. I'll reduce the frequency of watering but not eliminate it.

3. You'll find out next spring.

Thank you once again for all of your help. That really clears up the dendrobium issue, since I knew it’s ancestors had tropical conditions and was wondering why it would need a winter break.

[Roberta]

Originally Posted by Nicolasdperez

Thank you once again for all of your help. That really clears up the dendrobium issue, since I knew it’s ancestors had tropical conditions and was wondering why it would need a winter break.

Actually, Den. lindleyi (aggregatum) is a species from a wide swath of southeast Asia -considerably north of "tropics" and grows in the 650-1400 m elevation range. So it experiences a seasonal variation of climates - heavy monsoonal rains in hot, humid summer, but in winter very little rain, much brighter light (due to lack of cloud cover), cooler temperatures, and shorter days.

Low-elevation plants in the tropics may or may not get seasonal rainfall differences, but get pretty uniform temperatures and day length throughout the year, very different from what this species receives in habitat.

[Fairorchids]

To go back to your question, yes, temperature reduction is part of the trigger mechanism, and so is an increase in light. These plants come from deciduous montane forests, which have a distinct dry & cool fall/winter season.

In an environment with other plants, which do not appreciate significant temperature reductions, it is harder to provide that condition for the few plants that would like it.

When I realized that my mature aggregatum had never bloomed for me, I put it high on the northern gable in the greenhouse in late October. I did not water it all for 4 months. The canes did not shrivel, and by late February it had multiple inflorescences. Only then did I start watering again.

[Shadeflower]

I know I wish I had a greenhouse and kim I hear what you are saying its just what I am thinking is ok he moved it to receive more light and in winter light hours reduce.
At the same time you fiddled around with it thinking you are making a difference.
Sometimes arguably we do make a difference but sometimes my orchids surprise me like one of my worst cared for is growing the biggest cane ever this year whereas others I am giving all the care and light and temps etc just don't want to respond. It's sod's law sometimes. You can do all the right things or not, come to wrong conclusions which I am speaking from experience, I don't think any grower doesn't form wrong conclusions at times.

So there is no arguing that orchids need light, water, air etc to grow. Temps and light hours give the plants signals.

I grow under artificial lights so I can control the timing and watch the results perfectly. In a greenhouse when the sun doesn't shine as long every day and it gets colder as a result is when you reduce watering but like nic asks, which came first the chicken or the egg?

Is it the reduced lights hours and reduced temps or is it drought that sends a signal for the orchid?

A greenhouse grower can never ask to delay winter by a month. I have no problem providing that.

What I always found was that dendrobiums are often considered a beginner orchid but I find some of them quite challenging. People in a greenhouse do seem to struggle less with dendrobiums. Apart from a few exceptions I don't think dendrobiums are worth the effort half the time.

Not if you compare them to Catteya's. I know each orchid is unique in its own way but dendrobiums are slow growing, aggravating in the case of the aggregatum (by being slow lol) and the thin roots rot easier in winter...
Then add in the keiki problem and they might be branded a beginner orchid but who here hasn't struggled with dendro's at some point?

[Roberta]

I think it is totally impossible to generalize with any accuracy about Dendrobiums... Which ones? It's a huge genus with multiple sections, each of which has very different needs. And even within sections, different species have variation in their needs. Hybrids are yet another story. So... there is something for everybody. And I think it safe to say that nobody can generate the correct conditions for all of them. Find the ones that you like that also like you and your conditions and enjoy. Likely, a different subset of the genus than what works for me. (And there's a certain amount of trial-and-error that is inevitable, especially if you reach out beyond the most common... but really rewarding when you succeed with some very special gems)

This introduction to the genus (focus just on the species, hybrids add another layer of complexity) by Jay Pfahl of IOSPE sums it up:

"Dendrobium is the second largest genus after Bulbophyllum with over 1200 species ranging through all parts of Asia and the Pacific and is the second most common orchid genera in cultivation after the Cattleyas. Characterized by a cane-like, epiphytic and sometimes lithophytic, sympodial, pseudobulbs that can be any size or shape, with flowers that last for 1 day to months. They are found from India east through all of Asia and up into China and then out through all the Pacific islands including Australia to the south. It is a very diverse group and potting and cultural requirements need to be customized for each species individual environment." (Emphasis mine)

[Fairorchids]

Roberta,

You are entirely correct.

However, we started with specifically aggregatum.

I expanded my response to also cover the Australians (kingianum & speciosum) and nobile/nobile hybrids, since both closely parallel what should be done for aggregatum (and, there is another thread going on based on nobiles).

[Roberta]

Originally Posted by Fairorchids

Roberta,

You are entirely correct.

However, we started with specifically aggregatum.

I expanded my response to also cover the Australians (kingianum & speciosum) and nobile/nobile hybrids, since both closely parallel what should be done for aggregatum (and, there is another thread going on based on nobiles).

You did, indeed, constrain the species and groups that you were discussing, but Shadeflower's comments seemed to address "Dendrobium" as a whole, and that's what I was responding to.

[Shadeflower]

when it comes to taxonomy I am not the one to be reliable. Like pointed out there are 1200 differnt ones. Obviously I haven't grown them all and am not planning to.
Still I've grown a few of the most cultivated ones in the hobby, you either have the nobile types, the denphal types then you have the mini dendrobiums and the latouria dendrobiums + others.

My comment was purely my own preference based on my experience. I really like the latouria dendrobiums. So if you consider it from my point of view that the others generally (not all of course) only flower once a year for a brief time.... then they are imo not worth the space in my limited grow area.

When I first started exploring all the great new varieties that were available that I had overlooked in the past I didn't know which orchids grow how or what fragrant meant.

They all have their advantages and disadvantages. Like Cattleya's are very fragrant and can fill a room in some cases but the flowers don't last long. Fragrant phals are not as powerful but the flowers can last longer.
Dendrobiums generally don't flower very long. But the latouria types do so that makes a difference that is easy overlooked when just popping a new orchid into the shopping basket.

Didn't want to cause a ruffle talking badly about dendro's. It would be boring not having them too so maybe I am underappreciating them but mainly because when you buy a phal you can expect to see at least 1 flower within a year (if it was blooming sized). Again I might annoy by generalizing about dendrobiums but with dendrobiums my experience has been far from that.
For me what would happen first is the roots would rot. Then keiki's would form. Then it wouldn't like winter approaching because it wasn't used to my growing conditions yet. After a year of settling in things then turn around but I didn't know any of this and you could say I got some great phals and not great dendrobiums, ah who knows, maybe everyone should form their own experiences. It's just a shame that dendro's will most likely be the orchid I will relocate if I run out of space. They end up getting far bigger than what you buy initially and they don't flower as much as a cattleya.
Ok again I am generalizing and without growing them all one can't discover which ones one likes I suppose.

[Roberta]

Example of some more unusual ones... I have given up on Den. cuthbertsonii. Most of the time my conditions are OK, but then we have a hot spell, and I lose them. Den. glomeratum, generally considedd a warm grower but very adaptable, grows easily for me (all of this is outside...) Gorgeous hot pink blooms with orange lip. Well, there is now available a hybrid that is 3/4 Den. cuthbertsonii, 1/4 Den glomeratum. (Den Swiss Mountain Palace). Flower looks like Den. cuthbertsonii on steroids (same form, larger).Floriferous. Flowers last for months. And grow for me easily. So there are lots that are rewarding, don't take forever to bloom, and if one doesn't work, try another...