What yellow tree peonies do you like, Capice? I know it's not popular but my favorite is still Alice Harding. It's a tiny plant, only a few feet high at most, with the prettiest huge yellow blooms. I planted it behind a 3' or so retaining wall at both gardens I've had it planted in, since the blooms are so big and heavy they face down and don't display as well at ground level. Could probably put it in a pot in the new garden, wouldn't survive the zone 4 winter at the old house.