|Phlox 'Bright Eyes'|
Pholx paniculata, the major parent of the tall garden phlox, grows wild here in the neighborhood; I've seen both magenta- and white-flowered forms in the woods down by the creek. Save your garden space for the improved, cultivated forms and hybrids.
Years ago I visited an old garden which, to judge by what was left when I saw it, must have been something to see in its prime. The thing which really caught my eye and my imagination was a big border (12' x ?, but long) which had become overgrown by tall phlox. They were not in bloom when I saw them (that's where my imagination helped) but their sheer numbers made it obvious that they would put on a great show. A great show, but a relatively quiet show: for the most part, phlox colors are soft colors, old-fashioned colors. The colors are mostly harmonious and lend themselves to mass plantings. And, most of them are softly fragrant.
They cross freely among themselves, and as a result old plantings typically have self-sown magenta interlopers. Attempting to eliminate these by pulling them out does not work: any roots left in the ground will soon send up sprouts. This is as true of the interlopers as it is of the choice varieties, and an old trick for propagating these choice ones is to cut out the center of the clump and then wait for the ring of sprouts to appear at the edge of the cut.
Old books sometimes claim that tall garden phlox bloom from early summer into fall; that might be true in the cold north, but here the main, large stems have a bloom period of about two weeks, the same bloom period seen in most summer blooming perennials. There are two good reasons to remove the spent blooms: to prevent seed formation and to encourage the plants to bloom again later in the summer.