Not necessary :-)) Many of mine are budded, some even in bloom, and we have had frosts off and on for weeks, with temps getting as low as the high 20's. The last one was just earlier this week. No sign of any damage, even on armandii, which is a far less hardy species than most.

As an aside, we're supposed to break 60F this weekend for the first time this year - yahoo!!!!

Thank goodness, My clematis have only been in the ground for a couple of years but those babies get bigger and better every year and this year several of them have tons of buds so I was hoping they would be fine. Thanks for answering me so quickly. Judy

Yep, the plants are pretty resilient as long as the cold doesn't last too long and the buds aren't too developed. I worried about montana Grandiflora one year and it got by even though we were around 30 degrees or so. That is not to say however that I won't be out with blankets as added insurance should we get the cold weather they are forecasting for Monday night.