Have you planted roses in the fall with success yet? When are the roses supposed to arrive? Fall planting in the north is always iffy. I would definitely not worry about fertilizing in the fall. I would be more concerned about winter protection so they survive the winter, esp. a floribunda and grandiflora.

I agree with veilchen. And FYI, Osmocote only works when the weather warms up. It is a time realize and takes warmth for the little capsules to become permeable and release the fertilizer.

I tried a couple of own root peace roses from J P with no success. I have no idea when JP will send them. Last Winter they sent me Amarylis gifts and the replacements froze in transit.The replacing roses did fine.

I'm going to add Osmocote to the soil/potting soil when I plant in the fall and use lots of mulch

Fall-planted bare roots (Palatine) worked very well for me last year; no fertilizer applied at planting time; most of canes are underground, so you don't have to worry about winter damage.