I'm going thur my seeds,getting ready to toss some of these babies out into the cold and wet. I received some cosmos Dbl. Click in trade last year,waited until March to direct sew and got a VERY POOR gemination so I bought some more with direct sewing in mind for now.Also had same results w/ coreopsis Quills and Thrills so purchased some more of those with plans to do the same. Let me hear about your winter sewing experiences with these two.
I"ve had good success winter sowing Cosmos and Coreopsis. we are not the same zone, and they were not "Double Click" or 'Quilts & Thrills' .
I'm sure I have some that do come back from fallen seeds, so you could probably do either or... but if you did not have much luck direct sowing, why not winter sow them... less chance of the seeds washing away or getting eaten by birds or critters.