Q.Blue flax
Can Blue Flax perennials be split? If so, when is the best time of year to do so? If not, how can I get more plants from the one I have?

Certified GKH Gardening Expert
Blue Flax is difficult to divide, but some people have been successful at this. The best way to propagate this plant is by seed. Allow the flowers to go to seed; when the seedhead dries out it is ready to collect. Sow the seeds in the garden the next spring, or start seedlings indoors a few weeks before the last frost.
https://www.gardeningknowhow.com/garden-how-to/propagation/propgen/dividing-plants.htm