If they are really thick and most likely won't bloom, you could thin out some now and maybe add a bit of a balanced fertilizer, like a 10-10-10. Just a bit, don't over do it. Normally we do the thinning after bloom, and replant after the clumps get too large, but it's early enough you might still get some bloom from the rhizomes you leave alone. I'm not sure how far they have progressed in your area.
