Creeping Phlox Browning in Summer Heat: Normal Dormancy

A gardener in Central Missouri notes that lifting the foliage of their creeping phlox (Phlox subulata) reveals brown, dry stems underneath, despite watering every two days in hot, humid weather. They fear cutting it back will harm the plant.

Understanding the Growth Habit

Creeping phlox spreads by underground runners, forming a dense mat. As the plant ages, the center naturally becomes woody and brown while new growth occurs at the edges. This is normal summer dormancy, not a sign of death.

Care Recommendations

• Do not overwater. Water deeply once a week if no rain; constant moisture encourages rot.
• Leave the brown foliage until fall cleanup. It protects the crown and stores energy.
• In fall, gently rake out dead material. The plant will return green and floriferous next spring.

Long-Term Vigor

Every 3–4 years, divide the mat in early spring or fall to rejuvenate the center and prevent die-out.

Your phlox is behaving normally—relax and enjoy its spring carpet of color.