leave them till mid spring then cut the dead stuff off.they can recover amazingly well sometimes from the base.in future just tie the leaves above the growing tip rather than rapping them .they arnt so botherd about the cold as they are the wet.you can tie a few times so the leaves go into a point.this way the snow has know wear to lay and the bud is protected bye its own leaves .most plants dont want to die and have an amazing capassity to grow back.unless any plant is apserlootly bone dry and doesnt grip in the soil then theres always a chance. i hope ive helped take care bye for now .