Same here. While most of the trees are turning yellow and shedding leaves, my perennial grasses, hostas, agapanthus and even summer bulbs are still 'lush' and green; though we haven't had any snow (but almost freeze temps).
While snow needs freezing temperatures to stay like that, it's also a good insulator for covered plants against those freezes, so perhaps that's why. Just let it take its course.
