image by taliesin: http://morguefile.com/archive/display/161437
Phlox is an old-fashioned perennial that has been welcomed in the home landscape by generations of gardeners. Phlox begins flowering in mid-summer and provides at least six weeks of blooms. Phlox flowers come in bright shades of ruby red or purple, or subtle tints of white, pink and lavender atop tall, bushy stems. They are particularly easy to grow and require only the most basic pruning to keep them healthy.
Prune each phlox plant to no more than six stems when the plants reach about 6 inches tall. This will divert energy to the remaining stems, and the phlox will be healthier and produce better blooms.
Remove phlox blooms as soon as they fade, either with your fingers or with a good pair of garden shears. The remaining blooms will be larger and brighter. Prune away the upper set of leaves as well, to promote air circulation and prevent disease.
Prune the phlox to the ground in autumn, leaving a few short stems so you can remember where the phlox is planted. It may seem drastic, but the phlox will return in all its glory the following spring.