They should be cut back to the ground when the foliage turns yellow and begins to fall over in the fall/winter. Fertilize or top dress with a good compost or compost tea in the early spring. You can do some pruning in the spring to keep the plant stockier and fuller. Be sure to keep good air flow around them as they will develop powdery mildew with our humid air.

Debbie, I can't say enough good about this plant., Mine are still blooming and have been in bloom for months. Four Season is correct about air cirulation but David is more resistant to powdery mildew than any other Phlox I have grown in Georgia. I also cut off dead blooms and get reblooms for weeks. Make sure you have it in full sun . Don't be afraid to prune.

I have this plant to and love it. I have scattered some of the seed heads around. Does it reseed like crazy or is it manageable? I am growing it near Party Girl miniature hollyhock and I don want the phlox to overtake it.

My Phlox seeds around but not aggressively, just enough to keep me happy. If one plant dies, another is there to replace it. Easy to pull out unwanted seedlings.