Oncidium growth habit

[Dumb chemist]

I have a number of Oncidiums. My Onc leuchochilum and ornithoryhchum (excuse my spellings) show normal (?) growth with pbs coming from a central place slowly moving out from the center as new pbs are added each year.

On the other hand, I have Onc's. "Gower Ramsey" and "Sweet Sugar" that show a vertical growth habit. That is, a pb is at the surface of the bark mix. The next bulb is growing about a half inch above the bark mix off the first bulb. The next bulb is off the half inch high bulb by about a half inch making it an inch above the bark mix, and so on and so on.

Am I doing something wrong with these 2 Onc's to cause this growth behavior? Both Gowers and Sweets are growing in terra cotta pots using a standard orchid bark mix. Is attaching them to cork bark slabs considered better?

[WhiteRabbit]

I don't think you are doing anything wrong - many orchids, especially epiphytes like Oncidiums, Cattleyas - can have a tendency to "grow uphill' (as I call it). Some do so more than others.
Mounting is a definitely an option, but not "necessary".

[King_of_orchid_growing:)]

Gower Ramsey and Sweet Sugar end up being fairly large. I'm not sure mounting them will be an easy task.

But the growth habit you speak of can be normal for some orchids. Others are pretty good about not "climbing upwards" in pot culture.

[Junebug]

Originally Posted by Dumb chemist

I have a number of Oncidiums. My Onc leuchochilum and ornithoryhchum (excuse my spellings) show normal (?) growth with pbs coming from a central place slowly moving out from the center as new pbs are added each year.

On the other hand, I have Onc's. "Gower Ramsey" and "Sweet Sugar" that show a vertical growth habit. That is, a pb is at the surface of the bark mix. The next bulb is growing about a half inch above the bark mix off the first bulb. The next bulb is off the half inch high bulb by about a half inch making it an inch above the bark mix, and so on and so on.

Am I doing something wrong with these 2 Onc's to cause this growth behavior? Both Gowers and Sweets are growing in terra cotta pots using a standard orchid bark mix. Is attaching them to cork bark slabs considered better?

I don't think you've done anything wrong. My large SH grown Sweet Sugar, had the same growth habit that you're describing. It wasn't a problem at first, but the roots on newer stacked growth began dying because they couldn't reach the moisture and the entire plant ceased spiking. Frequent mistings did not resolve the issue and I really became concerned when the young bulbs began to shrivel and leaf tips turned brown.

In Spring I divided the plant into smaller 3 to 5 bulb portioned plants. I also removed some old inactive backbulbs and placed them on the surface of a pot of moist lava rock. The divisions have grown well. One recently sent out 2 spikes and I gave it to my daughter. The backbulbs have growth too, but I haven't potted them up yet. In the future I might try mounting a few of them just to see what happens. Experimenting can be fun, and it sometimes has it's rewards.

My sweet sugar grew and bloomed so well during the first 2 1/2 years. She was rapidly filling out her 7" pot and I was hoping to bump her to a larger pot and cultivate her as one large specimen sized plant. It became obvious that this was an impossible dream due to her stacked growth habit. With the exception of my daughter's new plant, there were no blooms this year. Next Spring all of the divisions should be spiking and that will be a lovely sight.