The worst thing that you could do is to go out there, the day or so after a freeze, and start cutting your cannas. That's because the new shoots are benefiting from the protection of the old ones.
So, just don't look at them for a while. I noticed the forecast is to be warming up pretty quickly, so that's the time to do the cutting, not when it's cold.
When the overnight temperatures are no longer getting close to freezing, that is the time to prune. And prune hard! Cut the big stalks all of the way to the ground. Don't worry, the new shoots, which you will see, will grow back very quickly. Yeah, it's a big job, but I count it as part of my *cardio* workouts. Get a trash bag, and fill it up.
But for right now, leave them alone. If you get all energetic and cut back too early, while it's still very cold out there, the new shoots will get frost burn. Let the old frost-burned top leaves protect the new shoots for a little while, and you will be rewarded with beautiful canna leaves in a few days, without a trace of frost burn.
|Cannas growing back after a very hard pruning.|