Inducing blooms in bulbophyllums

[malteseproverb]

I have several bulbos that grow happily throughout the year, but I have a hard time getting mature pseudobulbs to bloom instead of putting out new growth. Is there a trick to this? Whenever a growth matures, it usually just begins putting out new growth instead of a bloom. Can a mature pseudobulb bloom even if it has put out a new rhizome and a new pseudobulb? I'm assuming not. Is there a temperature or moisture requirement to getting them to get around to blooming?

The bulbos I have are as follows: sumatranum, longiflorum, mastersianum, lobbii, medusae, and Elizabeth Ann. The last two are very small rescues so I don't expect them to bloom for at least another year.

I keep them very moist. The longiflorum is mounted and I water it twice a day in summer and once every day or so in the winter. The others are in sphagnum in net pots or similar wide shallow pots with lots of holes. I water as soon as the sphagnum approaches dryness, but I never let it get crispy. In winter I keep them in the same place I keep plants of other genuses like catts, dens, encyclias, oncidiums, etc. that bloom regularly. They're outside in shade in the summer so temps are around 60-95F. Winter temps are 60-75F. I have a humidifier in the winter that keeps RH at 50% or more. I'm a very lazy fertilizer and don't bother to do it at all in the winter.

[bethmarie]

I'm interested to hear the responses you get. I've got a setaceum that grows like a weed, but hasn't bloomed in a year and it's way bloom sized.
I think for a while I was over fertilizing, but I dropped back on that months ago and still no blooms.

[Ray]

Originally Posted by bethmarie

I think for a while I was over fertilizing, but I dropped back on that months ago and still no blooms.

It can take a very long time for plants to recover from overfeeding. When I came to the realization that I was doing so, getting great growth but poor flowering, and switched to my current 25 ppm N regimen, it was easily 18-24 months before I started getting regular, reliable blooming again.

[bethmarie]

Originally Posted by Ray

It can take a very long time for plants to recover from overfeeding. When I came to the realization that I was doing so, getting great growth but poor flowering, and switched to my current 25 ppm N regimen, it was easily 18-24 months before I started getting regular, reliable blooming again.

Ah. Well that's longer than I'd anticipated/hoped. Again, from the orchids, "Patience, grasshopper." I really need to grow some weeds. It suits my type A personality better.

[King_of_orchid_growing:)]

If there is already a seasonal temperature differential where the orchids are growing, then the problem might be that there is not enough light.

Some of the Bulbophyllums you listed can handle moderate indirect bright light.

To answer your question, yes, in general, a mature pseudobulb can bloom despite having already grown a rhizome and a new pseudobulb.

I have not fertilized any of my orchids for years now, my Bulbophyllum taiwanense has not skipped a beat when blooming. They bloom every year. Not fertilizing your Bulbophyllums every-now-and-then is not a major factor for your plants not blooming.

Over-fertilzation usually causes problems with root-tip dieback, which can lead to leaf tip dieback, (but not always). I don't think this is likely a problem with not getting a Bulbophyllum to bloom unless all the roots are gone.

As a side note, they [Bulbophyllums] still need a dry out period before watering. Bulbos can tolerate drying out between watering. Even something like Bulbophyllum reticultum, (a species with thin leaves and a very flattened pseudobulb), can handle a brief dry spell, (by brief I mean 2 days), without a noticeable issue.

To recap, it kind of sounds like from your scenario, the problem is that the Bulbophyllums may not be blooming because of a lack of sufficient light.

[malteseproverb]

That's possible but I keep them with other high light plants that bloom regularly. New growths are usually bigger than prior growths. I have some of these under lights. I actually burned the lobbii over the winter keeping it too close to the lights. I also burned the medusae outside a few weeks ago... I say this because I actually have a tendency to give my plants A LOT of light.

I'm glad to hear some of these older growths could bloom, but how do I trigger it? Last summer, I kept the longiflorum hanging with a maxillaria tenuifolia, encyclia bractescens, and dendrobium ejerii in my yard. Each of these produced so much new growth--the encyclia I think had 12 new pbulbs. The longiflorum produced five new pbulbs, all of which were huge. They all, except the longiflorum, bloomed profusely over the winter. Maybe the bulbo didn't get enough light in the winter, but why would that prevent these 5 bulbs from blooming before that? How come these supposedly higher light plants bloomed so well and the bulbo didn't? The ones that I kept under lights all winter managed to put out large new growths over those months and they still haven't bloomed.

[King_of_orchid_growing:)]

How many pseudobulbs do these plants have?

[malteseproverb]

I'm at work so I'm consulting photos. Here are pics of my two largest, the longiflorum and the sumatranum. The former is hanging, not the best photo but you can see what I'm saying about the other orchids I keep it with! I think I see 15 leaves on the longiflorum. It has put out a few new growths since then. The sumatranum I dropped and it lost one of its leaves (oops) before this photo was taken. This is a photo of me recently repotting it. It has 6 backbulbs and 3 leaves and now it's growing another rhizome. My others are smaller. The lobbii has at least 4 bulbs. As mentioned before the medusae and Elizabeth Ann are too small to bloom.

[CourtneyT]

My Bulb has the same problem. I helped grandma divide her Bulb and got some pieces mounted in early 2016. Each division had about 2-3 pseudobulbs at that time. It has been 2 years since than. A lot of new growth, but no blooms. I only watered it twice a week. It got totally dried out in between. I'm wondering if that's my reason of not blooming. Or maybe it's still not fully matured.

[King_of_orchid_growing:)]

There are really two triggers. Temperature differentials and light. There are no other special tricks.

The temperature difference between seasons, and temperatures between night and day.

Lighting has to be strong enough.

Watering less or more will not do anything to get then to bloom.

Just waiting is the only other thing to do.

---------- Post added at 01:14 PM ---------- Previous post was at 12:59 PM ----------

Originally Posted by CourtneyT

My Bulb has the same problem. I helped grandma divide her Bulb and got some pieces mounted in early 2016. Each division had about 2-3 pseudobulbs at that time. It has been 2 years since than. A lot of new growth, but no blooms. I only watered it twice a week. It got totally dried out in between. I'm wondering if that's my reason of not blooming. Or maybe it's still not fully matured.

3 or 4 bulb divisions usually do not bloom so readily. Once they get to anywhere around 6 - 7 pseudobulbs, they tend to bloom more readily if lighting is adequate and if there is enough of a temperature difference between night and day and between the seasons. The temperature differences should be 10 F - 15 F.