British Columbia: Moving Chinese Ground Orchid - Bletilla striata alba

The single Bletilla I bought several years ago has now spread to produce about 12 stems, but the stems are quite far apart and scattered over an area of about 12" x 20". The individual flower stems currently don't make much of a show and some are coming up half-hidden under other plants.
If possible I would like to group the stems closer together to be a bit more of a feature, but I want to do it carefully. Are these widely spaced stems divisions of the original plant connected by runner roots, or would each have grown from a seed? How early in the fall can I transplant them? How deep do I need to dig to avoid damaging the rhizomes? Do I need to keep them connected? Could I bury some kind of ring around the new 'clump' to confine any new plants to an area about 10"-12" dia.?
Would they tolerate being interplanted with a low perennial groundcover like Labrador Violet, or would the competition be too much for them. Any other suggestions for low annual or perennial companion plants to set them off, or increase their impact would be welcome.

 

Greetings from North Vancouver, where I have had the mauve variant for about 20 years. I periodically divide it and did so mid-April as new growth appeared. They are quite shallow rooted, so there is no trick to dividing other than to dig to about 4" deep, with several growth eyes for a new clump. I replant whatever appears in my shovel without further division, and don't discard what appear to be back bulbs.

My 2020 transplants were very forgiving and almost all of the transplanted clumps produced flowers.

Mine are tidy, increase slowly, and are fairly confined. After not dividing them for 10 years, they more-or-less increased their footprint to 18",and with > 30 stems.

Interested in trading some of your whites for some of my mauve?

Cheers

Gary