The plastic from the tarp touching the fronds is what caused the burn. Next time try, something like frost cloth or a blanket. As far as when to cut the fronds off, not until they are completely brown. As long as there is some green, it is still providing food to the palm.

Sorry to hear about your trachys. I hope that they come back. My Med fan palm is also brown and crispy looking but I am leaving all the fronds on because it will provide protection during the rest of the cold this winter (and there's going to be more heading our way soon). Even if there's still a little green on the petioles, that will help give the plant energy in the spring like Brad was saying so I wouldn't prune until spring when the weather warms up. I won't be pruning any of my stuff until the days are longer and they are already starting to grow back well and have more green.

I hope your trachys pull through!
-Alex

Thanks for the info. Someone told me a while back that trimming the lower fronds would help the overall health of the tree, because they still draw nutrients. Over the past 10 days or so, I probably trimmed half of them, but there are still quite a few of the upper fronds left on each tree. Glad I asked before going any further.

Any further advice on getting them through the remainder of the winter would be much appreciated. I planted them 5 years ago when they were about 4 feet tall. I winterized them the 1st 2 winters, then haven't touched them since, as they were pretty well acclimated. Every year they look kind of rough early spring, and come back wonderfully for the summer/fall season. They are just under 10 feet tall now, so they should be pretty hardy and mature.