In their place I planted Salvia Leucantha. I've already got a few of those in the larger bed against the fence, so decided to make them a recurring plant in the garden a) for continuity and b) because they're pretty. Not the ones with the white fuzzy parts, only the solid purple ones.
Semi-ironically, I pulled the Salvia Leucantha out of the middle bed because they just seemed to overwhelm it. I replaced them with more Canna Pretoria and some 'Lafter' rose I had languishing in a pot on the patio.
I tried both "Sweet Pea" rose and Gruss an Aachen Pink along the border of the large back bed in Season 4. The Sweet Pea got bad black spot and Gruss got powdery mildew. Both are GONE!
In their place, the reliable and lovely 'The Fairy' rose.