How to divide climbing oncidium?

[Zabeta]

Hi everyone,

I just received an Oncidium Lemon Heart 'Baby Face,' delivered from Hawaii. It came with essentially one plant growing on top of another, like so:



My problem is, first off, I live in a desert-ish climate in northern CA, so those aerial roots are going to die. I need to divide and repot and try to turn the roots on the aerial plant into non-aerial roots.

Unfortunately, the aerial portion of the plant only has two mature pseudobulbs and one still-maturing one. I realize that three is the accepted minimum, but in this case the only logical division is to take the aerial portion off.

How do I do this? I've never divided a plant before, and I really don't want to harm this thing. Can I even do it in this case, since there aren't really three full p-bulbs on the part I want to take off?

Any advice would be appreciated!

[WhiteRabbit]

Many epiphytic orchids (like Oncidiums) will have a somewhat vertical growth habit - some only slightly so, others more extreme.

You can repot with the rhizome more level (will cause the plant to look angled). You don't need to get the newer growth all the way down to the media - just closer will help.

To divide, just cut the rhizome with disinfected floral pruner, or a disposable razor blade (single edged replacement blade for box cutter).

[Zabeta]

Thanks so much for your reply, Sonya. I ended up just dividing it however I could, and it went pretty well. Each half has a good amount of roots, and I just potted the aerial roots into a pot. I hope they do okay!

[silken]

I found that some of these can have old leafless bulbs potted down into the media so that the new higher parts can sit at media level. It doesn't seem to make them rot when I have seen it. Just something for if you need to re-pot in the future

[Zabeta]

Thanks, Silken! I did have to put one small old pseudobulb sort of down in the media, so it's good to know that isn't automatically a death sentence! And I have such a dry climate that my least concern is rot anyway. I appreciate the tip!

[WhiteRabbit]

Originally Posted by Zabeta

Thanks so much for your reply, Sonya. I ended up just dividing it however I could, and it went pretty well. Each half has a good amount of roots, and I just potted the aerial roots into a pot. I hope they do okay!

Sounds like you did good

I've also not had trouble burying old pbulbs