Well, I'm in Z5 and I know I have a good 8 weeks of really cold weather left. I think you should just go ahead and WS. Some things don't even need stratification anyway and it will be a fun thing to do. I just bet if you do it, you will keep on doing it every year!!!!! What a way to pass the cold January!

I've only done 12 containers so far and there is too much snow (4-5 feet) out where my containers go to put any new ones out there. Because of that I'm thinking about reducing the number of perennials this year and do mostly annuals, herbs, and veggies.

But you still have plenty of time if you can get your containers out there. Most perennials seem to do okay with about 30 days cold stratification which we have left in this season. Some don't need any. I just did a germination test on some seeds I collected last fall from Liatris spicata 'Kobold' and Heath Aster/Aster ericoides. Had lots of healthy germination after about 1 week - with no cold stratification at all.

Not sure if you have enough time for most trees and shrubs.