Splitting a mature potted clump is quite an exercise. Normally in the alpine house, I had a "plant" outside all summer and thought it about time I looked at dividing it. Very brittle and very congested. From a 6/7" pot I got 3 clumps with 3 growths, 1 single and 4 single growths with few roots, plus a large clump of roots with no obvious growing points. I did it under water but it was still very difficult.
After 4 weeks the root clump now has 2 growths, and all the rest look OK, so far. Never had any seed on it that I am aware of.