I've had this plant in a container for several years. Every couple of years I put it into a larger pot. It's in a 12 inch pot now. I'm wondering if it would be better to divide it, or continue to put it into larger pots. So far it is continuing to bloom well each year and doesn't seem to be getting puny like daylilies sometimes do when they need dividing. However, the roots are very tightly tangled. So what do you think, should I divide it, or just pot it up into another larger pot?