You’ll need to remove the entire phlox plant from the … … They get lots of hot afternoon sun from the south. Creeping phlox, Phlox subulata, is a stunning low-growing perennial that creates a striking carpet full of 5-petaled blooms in radiant hues of reds, purples, blues, pinks and whites in late April and May.Typically reaching a mere height of 6 inches, but often spreading to 2 feet, it is a great choice for a groundcover. The "creeping" will more than likely not begin until next spring as the plant is stressed and focusing energy on establishing roots. Feed the plants in early spring with a low-nitrogen fertilizer for best results. I will attach a picture. My Phlox is planted on a slope that has tons of water just under the surface. What could this be! The taller garden Phlox also needs good drainage but is not in flower yet here in the northeast. I know that my phlox that have been in the same area for 3 years are just now starting to bloom so you may yet get some flowers this year. The tops of the plants are fine and they eventually bloom. My yard is a huge drainage area for the nearby hills and is constantly draining all year about 1.5 to 2 feet below the surface. Garden phlox, or Phlox paniculata, is a perennial that blooms in late summer and comes in a variety of colors. As with most plants, phlox … I have phlox in various locations in my garden. I transplanted some phlox 3 years ago to a northeasterly location. Hi: I have had Bright Eyes Phlox for year's now, but this year I moved them, no problems till now. They start out each year green and healthy and then start to turn brown at the ground level, eventually continuing up the entire stalk. A good time to divide your phlox is during the early spring, late summer, or early fall when the plant is as wide as it is tall. The leaves on the bottom are turning brown and yellow and are dying and falling off, this doesn't look like the powdery mildew that is the phlox bane. However, this eccentric plant can require some specific pruning. Q: I have phlox plants in my back yard and every year about this time the leaves start turning yellow from the bottom up. However, on one group, the leaves are curling under themselves - with no sign of bugs, worms, flies, or mold spots. Phlox requires full sun and well-drained soil. I had to pull all of them in fear of … This year several of them have yellowing leaves and even look like they may not bloom. I have groups of phlox growing in my yard in different spots. What is wrong with my phlox? Phlox plants grow to be between 2-4 feet tall, and they can usually be divided every 3-5 years. Once the leaves turn yellow, some have turned brown and look dead. Asked July 2, 2015, 6:29 PM EDT.