Repot a plant and what's left is a backbulb. Right? Wrong. Let's look at an example of harvesting backbulbs.
I got this Anguloa virginalis in bloom a year ago. It grows in Colombia, Venezuela, Ecuador, Peru and Bolivia. It is a cold to cool growing terrestrial found in deeply shaded humid forests.
It had grown right up to the edge of the pot, so when the flowers had faded I removed two backbulbs for the purpose of making more room. The plant was moved away from the edge and the space was filled with sphagnum moss. I placed it on the floor between two benches, the place I thought most closely approximated their natural environment.
A well grown plant develops pseudobulbs that are as large or larger than the previous generation. Mine was smaller. Mine is developing three spikes, it had seven last year. So just by looking at the plant I can tell there is a problem.
You have to see the roots to really know the health of a plant. I popped the plant out of the pot and cleaned out the old sphagnum. The roots told the story. I had overwatered. There were some live roots but many were dead.
For the plant to be potted up decisions had to be made. One choice is putting the entire plant back into a larger pot with frest medium. If there had been masses of health roots, that would be proper, but with reduced root mass that would be overpotting.
I decided to reduce the size of the plant and put it back in the same pot, centering the new growth. For that to work, I needed to remove two backbulbs. I decided to keep them as a group rather than making them separate.
In a wet environment like mine sphagnum moss is tricky. It holds a lot of water, too much for Anguloa virginalis apparently. My Masdevallia plants do well enough, but they are in pretty high light. I needed another medium for this plant.
Rock is my favorite medium. It drains well and at the same time holds more water than you might think. I have three choices from what I have on hand. Marble pieces, lava rock and pea gravel.
Since I wanted the plant somewhat wet I decided on pea gravel. I did a top dressing of larger marble chunks on the main plant for looks. I will put it back in the same location as before and see what happens over the next year. I don't want to change too many things at once.
The backbulbs go under the bench. I had really good success getting last year's backbulbs started. It is potted in sphagnum but is in a higher light location.