White Sage in Maine

I live in Central Maine, USA, towards the mountains (near Sugarloaf ski area). One of the many seed I ordered from you folks this spring was white sage. I have a very nice stand now of white sage but last night a good friend informed me that it is not a perennial. Will my plants live outside over winter in Maine? You say tender perennial. What zone exactly do you think they are hardy for then? Would they survive outside where you are? Have you done that?
Any information would be greatly appreciated since last night was our first imminent frost!

White sage is hardy in zones 7 to 9. Since we are in zone 5, it is a tender perennial for us and would not survive our winters out of doors. Central Maine is on the border between zone 3 and 4 and the plant would not be hardy for you even if it were hardy to zone 5. You will have to plant them into pots and bring them indoors for the winter - or treat them as an annual and start fresh next year. You could of course try mulching at least some of the plants heavily as a trial and they may make it through the winter anyway. Winters have lately been rather mild for some parts of North America, while other areas have been colder than normal. This is probably due to the warming of the atmosphere and the resulting changes in wind patterns. If you are one of the lucky warmer areas, your task should be more encouraging.
You may not have noticed, but starting with the 2000 catalogue we only classify plants as perennials, annuals or biennuals and give the zones in which the plants can survive out of doors. For white sage, the "P Z7-9" means the plant is perennial, survives out of doors in zone 7 to 9.