Different species and varieties of phlox are longstanding nursery favorites for their delicate flowers and growing habits. Common nursery species include garden phlox (Phlox paniculata and cvs.), hardy in U.S. Department of Agriculture plant hardiness zones 3 through 8; creeping phlox (Phlox subulata), hardy in USDA zones 3b through 10; and sweet William (Phlox divaricata and cvs.), hardy in USDA zones 4 through 8. Spreading phlox (Phlox diffusa) grows wild in dry and mountainous areas throughout North America and is hardy in USDA zones 4 through 8. As widely used as they are, you may grow tired of your phlox or wish to remove it for another reason. Removal isn't particularly difficult and you have many methods at your disposal.
Pull the phlox out by hand, grabbing close to the soil line and pulling up the roots. Most phlox plants will come up easily, particularly in dry, rocky soils where a few species prefer to grow. In moister or clumpier soils, however, you may need to use other methods in conjunction with hand-pulling to get all of your phlox patch.
Dig up the phlox using a garden trowel or specialty weed-removing tool. In moist soils, you may have to dig a little more to get to the entire root system.
Spray the phlox with a commercially available, highly acidic vinegar. Acetic acid, found in vinegar, is a naturally occurring, non-selective herbicide that works by drying out the plants and killing them by dessication. Take care to cover the entire plant, but spray directly to keep it from drifting onto other plants.
Spray the phlox with a glyphosate-containing herbicide if you prefer. Glyphosate is a non-selective, chemical herbicide that is widely available at big-box stores, hardware stores and garden centers. As with acetic acid, take care to spray only your phlox as this product will kill, or at least damage, any plant it touches.