Answer: Gaillardia is very cold hardy (zone 4) as long as the location is a well drained one. In poorly drained or heavy or very rich soil the plants seem to be short lived and may not winter over well. Once frost has killed the tops back trim off the stems to about two inches, then when the ground is frozen mulch around but not over the crowns unless you use a light and airy mulch such as evergreen branches. Good luck!
Q&A Library Searching Tips