Do it now. They should survive though watch the watering.

Planting the lance-leaf or mouse-ear varieties should still be fine. Though we've not had much luck keeping the thread-leafs going more than a couple seasons and have read they can be a bit more fussy to establish and sustain. Locating them in a spot with low soil moisture/good drainage during the cool months will be more critical for new coreopsis of any variety than the low temps in your area - especially if you're on clay. Believe even the most tender hybrids are still rated to hardiness zone 7.

This post was edited by bostedo on Mon, Nov 3, 14 at 16:27

The only reason I would buy plants if if they had the color I was looking for as they do great from seeds almost anytime.