"warm" dendrobium nobile question

[palito]

Hello everybody. I am confused by these plants.

I got three dendrobium nobile type hybrids about three months ago. Vendor described them as being "warm growing". Plants were too tall for the pots and were falling so I just put them inside clay pots with lava rock around and forgot about them. They have not been fertilized but they do get water whenever it rains.

I looked today and I noticed that all are growing roots and are now attached to the lava rock, and are starting to grow new canes. They have been outdoors fully exposed. Temperature has been 55-45F day to night for more than a month. Isn't it too cold to be in active growth? They have not dropped leaves either. (were they supposed to?)

What should I do? treat them as if they are actively growing with no rest? Temperatures will continue to drop to 45-35 into january. Should they be protected since they are in active growth and not dormant?

[11Orchid126]

This is the site of Yamamoto Orchids in Hawaii. Yamamoto hybridizes nobile dens. I've been treating my nobiles the way Yamamoto suggests, and I've been very pleased with the results.

General Care

[kmarch]

Well first let's correct a bit of missinformation. It sounds like the vendor you bought them from either doesn't know how to take care for nobile-types or sold you plants that aren't really nobile-types. Nobile-type Dens are not warm growing. Warm growing orchids need minimum night time temps in the 65-70F range. Nobile-type Dendrobiums are cool to intermediate growers and like an autumn cooling off (necessary for blooming) and a drier winter. Also nobiles shouldn't be fertilized, or at least should be fertilized only very lightly at the start of their growth season.

Many Dens prefer to be very pot bound so it isbest to keep the in tight small-ish pots. They often look as if they're in ots that are way too small. Because of this they are often top heavy and you'll have to get creative in coming up with ways of preventing them from tiping over. I set the small pot inside a large clay pot with rocks.

It is not usual for nobile-types to be starting new growth at the end of autumn but if they are healthy and growing, I'd let them do their thing. Do not fertilize them.

[palito]

Thanks for that link 11Orchid126. Very detailed!

Thanks Kmarch. After reading that Yamamoto website, I think what the vendor meant is that they are a "warm tolerant" cross meaning they can still bloom without the chill. Maybe mine will only be forced to rest at lower temps or maybe not rest at all.

[Andrew]

Originally Posted by palito

After reading that Yamamoto website, I think what the vendor meant is that they are a "warm tolerant" cross meaning they can still bloom without the chill.

You're correct that one of the main aims of Yamamoto hybrid breeding is to reduce the need to chill them to initiate blooms so that they're more accessible to tropical and indoor growers. I have a few Yamamotos and while they certainly bloom well under typical nobile temps. However, one of them initiates flowers in late winter and again in late summer if I don't properly control the water, light & fertiliser, which I guess goes to show little the temperature drop needs to be for some of them.

[Aleksa]

I'm growing my nobile Dend on my balcony. I ve noticed some buds above the every leaf. temperatures are going below 5 C (41 F) at night and around 10 C at the day. What is the lowest temperature that Nobile can resist?

[Tobi]

Originally Posted by Aleksa

I'm growing my nobile Dend on my balcony. I ve noticed some buds above the every leaf. temperatures are going below 5 C (41 F) at night and around 10 C at the day. What is the lowest temperature that Nobile can resist?

Aleksa,
I not sure of the absolute minimum temp, but A few of the local growers
around here told me that low temps around 40F was optimal for their best
blooming.

[Aleksa]

It's great then. Buds grow very very slow, so I thought about getting them inside in warm place, but somebody told me not to do that because it will create a lot of keikis.

Thank you tobi!

[11Orchid126]

From what I understand, young buds can turn into keikis very easily. You might consider keeping the plants cool and dry as possible until you see that they are definitely buds. Once you see they are definitely buds, you might try to warm them up a bit. Don't jump from cool to very warm all in one fell swoop, though. Do it gradually.

[kmarch]

Originally Posted by Aleksa

What is the lowest temperature that nobile-types can resist?

I grow my Dens outside here in Melbourne. In winter the night time temps can regularly drop into the 5-10C region (40-50F). I do not have Yamamoto nobile-types so mine are the cool types, they're also kept very dry when it is cool like this.

[Aleksa]

Yes... i do keep them very dry. When I notice that canes started to shrivell and became soft I water them... That's about once in two weeks or even more rare. I'm not sure whether this my thing is Yamamoto, but I keep it as normal nobile...

[kmarch]

What it the point of warming buds up once you see them?

[jerrymeola]

I have hundreds of Nobile Dendrobiums in the shade house now. This is the start of blooming season for them in Florida.

They can easily take temperatures into the low 30s and I have accidentally let all my orchids go to 28 two years ago - nothing died. They like very blight light even higher than Vandas, although, they also flower well in lower levels

Buds will never change into keikis. Both can look about the same as they emerge but they will not change characteristics.

Keikis form from excess nitrogen. Never fertilize after August or they will not flower. Withholding water is not important for Yamamoto Dendrobiums. They are with my high light plants and get 15 minute waterings 2-3 times a week. I expect every plant to flower well. About half have already set buds in the current high heat.

I handle mostly Yamamoto Nobiles. The whites bloom earliest and prolific. They set buds this year when the temperature dropped from 95 to 75 while 50 is where they should start to set buds.

Den Red Emperor (one of the few fragrant dens) also is setting buds with the temperatures only going to 70 for about a week.

Palito,
I am a little concerned about whether you really have Nobiles. They do not grow roots very fast. It is one of the few blooming dens that does not get pot bound. Usually less than 1/3 of the pot has roots. They also do not usually attach to clay pots like most other Orchids. The growth you discribe and the new canes forming make me
believe they are common Den Phals and not Nobile. None of the ones I have grow new canes until the flowering is finished.

You will know when they finally flower. Nobile flowers grow from the cane not a stem.

Many growers all their name to the plant tag and this may help determine what you have.

[palito]

Thanks Jerry

Here is a pic of two of them. you can see at the base the new growth. roots came out of the bottom of the plastic pot and attached themselves to the lava rock around. Did they skip the rest period?


crosses are:
Den. (Crystal Pink x White Christmas) x Den. Fortune 'Hawaiian Sunset'
Den. Princess x Den. Gold Star 'Orange Royal'
Den. Exotic Rainbow x Den. Dream

[palito]

ok so almost a month after my original post, the plants kept growing new canes ( never rested despite the cold temperature) but recently they have dropped a few leaves and are now swelling something in the older canes. No clue if it will be keikis or flowers since they still get watered. i guess ill find out soon...

[Touria]

My dendrobiums are the worst, they wont do ANYTHING, ive had them for years and years, they're deciduous and I think they're a little shrivelled. anyways they grow and what not, but they wont bloom. i want to put it into dormancy, I've read that you're to put in a colder place and not water it.... but some of the stalks are so shrivelled that im afraid to do that.
What should i do?

[evagentry]

I also have a nobile type dendrobium that was covered in orange flowers and had new growth when I bought it, now it lost its leaves like it was suppossed to but it has 7 new canes started and some bumps on the canes, I hope I didnt do something to keep it from flowering , it is called a Star Class dendrobium if that means anything.

[Tobi]

Originally Posted by evagentry

I also have a nobile type dendrobium that was covered in orange flowers and had new growth when I bought it, now it lost its leaves like it was suppossed to but it has 7 new canes started and some bumps on the canes, I hope I didnt do something to keep it from flowering , it is called a Star Class dendrobium if that means anything.

Here is a link with a little information on your Den.

Dendrobium nobile starclass eng detail

[evagentry]

thanks so much Tobi, that was great of you!

[Gladys47]

I have 2 red emperors and I'm kind of mad at them! I've done everything yall said, to the letter! I have 2 buds on 1 plant!I was hoping for so much more. Maybe it's because it there, or it's first blooming? Maybe I'm rushing it and it's stoll not too late? Feb. is our winter month around here. What do you think? Gladys

[11Orchid126]

The problem may be the fertilizer. Dens don't like a lot of nitrogen. I use Dyna-Grow Bloom for mine, very low in nitrogen, which I stop altog