One plant I use as a guage for the severity of winter is Coryline australis. If these die back or are killed out-right, I consider it to have been a severe winter. They are hardy to around -8 to -9 centigrade (17.5f - 15.8f) for the brief periods we can encounter around coastal PNW. They will often show little damage for a month or more then suddenly flop over after the damage manifests itself. Most often, they will resprout with muliple shoots in spring. My coldest night was -6.9 celcius (19.6f) in late November and again this Cordyline has managed to stand tall. Seed grown in the spring of 2002, I hope it continues for a few more years. I've seen some recent pics from around the BC mainland that suggest it was cold enough to knock down these even in some favored regions like English Bay in Vancouver, BC. Are there any other 'exotic' plants you use to gauge winter cold? Cheers, LPN.