Bluegrass: I divided a fairly mature clump to spread them out. I did the division in the fall, and the following season all of the plants just kind of sat there looking somewhat sad and had a much shorter bloom season (started very late). After pouting for about a year, they all recovered and took on good vigor. I'm glad I did the dividing, as I now have a nice patch of 5 clumps rather than 1. Perhaps moving seedlings is more successful than dividing? One may want to be sure the seedling comes true first, but by the time it blooms it may well be at that 'resentment' stage. I'm certainly no expert...