Not at all!! End of February/beginning of March (or when the forsythia is blooming) is the traditional time to prune back clematis. Same time you prune roses or cut back warm season ornamental grasses :-) But even earlier in the year or later is no big deal....all a later pruning will do is delay the bloom cycle slightly.

here in much colder MI ... i might wait until i see buds ... before going whole hog on anything ... often ... but not this year.. its a die back to snow cover issue ...

and there is always the caveat ... of not tromping thru sodden garden soil and turning it to cement ....

ken

ps: one might also say.. that it later pruning will delay bloom because it will have to trigger new dormant buds to start growing.. as compared to the ones that are ready to go ... depending on warmth.. that might take the week or two ...which causes the delay ... again.. its regional.. i might get a warm snap.. and then a cold snap.. stalling active growth ...

Ken, If you notice, this was cross-posted to Northwest Gardening. And the OP is known :-) Clematis buds are already very present here, some are showing substantial growth and at least one species is in full bloom. No worries about fluctuating temps to below freezing. And minimal concern about any sodden ground as well. I've working in my garden off and on for the past few weeks. It's already showtime here!!

Did the cuts yesterday and yes, definitely substantial growth now but couldn’t stand the tangle. Thanks for bolstering my courage.

Nellie Moser blooms first on old wood, and later on new wood. Prune conservatively now, removing weak stems and such, then after the first flush passes, you can do some more to remove some of the older stems and encourage more new growth for later bloom. Jackmanii blooms on new growth, so you can hack the heck out of it and not lose flowers!

I hard prune all my Clematis!