Flowers but no growth in one year, plus shrivelling pseudobulb - Orchid Board

bellatulum · #1 12-11-2016, 11:51 PM

Hi all, I was wondering if anyone has had similar experiences to this and if so, can give any insight on what I can do. Here is the issue:

Last October, I purchased a Dendrobium bellatulum and it looked fine. It bloomed for me, several times actually, but it has never made any new growths. In fact, it had lost a pseudobulb, it completely dried out (it's the skinny one on the left in the before image).

The only thing it had grown was two roots, but they never grew very long and have since ceased to grow. Right now it's taking energy from another pseudobulb which is causing it to wrinkle and shrink and at this point I'm worried the plant it going to die because it's not producing any new roots and all the leaves are gone now.

The way I'm growing it is on a mount with some sphagnum moss in my home. I understand this needs a bit of a winter rest, but I've been spraying it lightly because I'm not sure the humidity in my home is enough to sustain it while it's dry.

My question is, has anyone experienced this and did your plant survive? What should I do, or is there anything I can really do?

Thanks!

estación seca · #2 12-12-2016, 01:37 AM

I am not familiar with this plant, but it looks like it has been severely dehydrated for quite some time. Generally mounts need watering at least once per day during their growing season, a little less during dormancy. Even if there's no rain there is usually dew.

Also, this may be a plant requiring high humidity. That would also cause poor growth.

bellatulum · #3 12-12-2016, 02:51 AM

Yeah, I've been watering it once a day throughout the year but still nothing grew. Maybe it is the humidity, although I haven't seen any articles that state specifically that it requires high humidity.

AnonYMouse · #4 12-12-2016, 04:00 AM

I'm not a big Den. grower and don't grow this one.

Besides the watering, need answers for these general culture questions:

What are your temperatures (min, max averages for winter and summer)?
What, how much and when do you feed it?
How much light does it get?

bellatulum · #5 12-12-2016, 11:50 PM

What are your temperatures (min, max averages for winter and summer)?
Winter: 18 - 22C
Summer: Hard to say, probably between 22 and 28C on average.
I'm aware it might be a little too warm for it, especially during the summer, but there you go

.

What, how much and when do you feed it?
What: MSU formula
How much: You mean the strength? The directions say 1/4 tsp per gallon so that's what I do.
When: During spring/summer, I think I did once a week

How much light does it get?
It lives at an east facing window, so it gets morning to early afternoon sun.

Sorry, I know my answers aren't super precise but I hope that gives you an idea of it's environment.

Thank you!

AnonYMouse · #6 12-13-2016, 03:44 PM

I don't have experience with this species. What I would do is push the winter conditions more, lower the temp a couple more degrees (15-16°C), drier and more light.

You don't mention frequency of feedings, so go to Firstray's and calculate N for 25-50ppm for every watering.

Just out of curiousity, take a look at the base of the canes with a magnifying glass. Look for tiny triangles.

bellatulum · #7 12-14-2016, 02:25 AM

Tiny triangles? You mean possible new growths? I took the plant off the mount and found two on the back. A ray of hope!

I've placed it in a clay pot, sitting on top of damp sphagnum moss. I'm hoping the evaporation and cool it down a bit and maybe the humidity will help as well.

Thank you!

NatalieS · #8 12-14-2016, 05:40 AM

Hello! I've grown bellatulum for a few years now. The culture is generally said to be a little tricky, but I think that I must just be lucky with my conditions.

First thing to remember with these is that they do not like their roots being damp/moist for an extended amount of time. Mine is mounted, and I would water in the morning so that the roots are dry by evening (mine is mounted with absolutely no moss or other media covering the roots). Keeping it in a very sunny spot helps with this, as well as fulfilling their light requirements (they will take a lot of high light very happily).

Second, I agree with AnonYMouse about bringing your winter temps down. I think they are quite temperature tolerant, but need quite a big difference between summer and winter temps (I actually grow mine cold/cool in winter).

I personally don't pay much attention to how I fertilise this species - it will just produce growths and flowers at any time and doesn't seem to have very distinct seasons. In any case, if the plant looks like it is struggling and has lost its leaves, I would stop fertilising since it's hardly going to be able to do anything with the extra nutrients. Also, remember that over-watering can look the same as under-watering - you will still get shriveled bulbs.

I would take it out of all media (leave it bare-root), and let the roots dry for maybe a day depending on the humidity where you grow. Then maybe just a light spray every morning for the next little while. Also, to bring temps down, perhaps best to put it somewhere shady since strong light is very harsh on plants that are already struggling.

I hope it recovers and you get a new growth!

bellatulum · #9 12-14-2016, 12:16 PM

Thank you NatalieS!

bellatulum · #10 01-20-2017, 01:59 AM

Good news! I have a new growth growing! I'm losing two pseudobulbs, the big one in my original post and a tiny one, but at least I have a new growth.

What I did was remounted it without any sphagnum moss, but put some spanish moss on top for humidity. Then I sprayed it in the morning. I was a little concerned it wouldn't be good enough since it's a little dry in my home, so I also water it in the evening. I also don't have it hanging at the moment and it's sitting on the windowsill where it gets the coldest.