HI Iluvpeonies. I am also upstate NY (zone 4b/5a).
I tend to throw everything together in my gardens
so i'm not sure if I have the discerning eye to say what looks good with what.
however. here are some things i've interplanted (* next to the ones that flower after peonies)
- creeping phlox
- phlox*
- hosta*
- cone flower*
- black-eyed susie*
- zinnia*
- dahlias*
- dwarf sunflowers*
- foxglove
One thing to note: If your area has big issues with powdery mildew probably best to avoid zinnia and phlox. Our winter temps kill off most of the powdery mildew so that give me some flexibility I didn't have when i was growing in zone 7.
happy interplanting!!