How to Prune Phlox paniculata 'Iris'?
Deadhead to prolong flowering, then cut down to the base in late autumn

Phlox paniculata 'Iris' · Phlox paniculata 'Iris'
Thrives in any fertile, humus rich, moist soil in full sun or part shade. Plants will benefit from good air circulation and from watering in extended dry spells. Water at the base if necessary, rather than over the leaves
Deadhead to prolong flowering, then cut down to the base in late autumn