Im in lower NY, zone 6a. Ive been too busy with moving to winter sow, but hoping to get some perennials set up this week. Is it too late for the "harder" stuff that definitely needs a long stratification, like tree seeds, etc?

I start my tomatoes/peppers/eggplants under lights on 3/1 each year and can safely set them out 2nd or 3rd week of May, but this is my first year attempting to winter sow perennials. Any tips are greatly appreciated!

~Kerry