EASY TO GROW FLOWERS = LATE SUMMER - FROST HARDY ZONE 3 (3-4 with protection) - 10 Most mums show hardiness to zone 5 but my past experience in zone 3 = no problem to get them to survive... But they need area that does not hold a lot of water in winter... Areas that hold water freeze more like an ice cube (VERY hard) than Ice cream. Too Much water kills most perennials you are trying to over winter... covering you plants with Hay or leaves will help a lot... Now you just have to watch for moles to not eat your plants. Height = 18" - 30" Spread width = 18" - 30" Full sun to part shade