Grandmother called this plant thrift, but it also goes by such common names as moss phlox, creeping phlox, ground pink, and moss pink. A drive along almost any country road in early spring will attest to the survivability and tenacity of this plant. In many instances it has grown in the same place for many years with little attention from the gardener.
Moss phlox is an evergreen, mat-forming, perennial that grows three to six inches tall. Clusters of five-petaled flowers literally cover the entire plant in spring. Clumps gradually spread as stolons creep over the ground and eventually cover an area approximately 18 to 24 inches in diameter. Recommended for Zones 3-9, it is not surprising that gardeners in most areas of the United States can grow this tough-as-nails perennial with no difficulty.
Given a modicum of care, moss phlox will grow well if thought is given to its placement and preferences at planting time. Choose a place in sun to partial shade. While preference is for moist, well-drained soil with a neutral to slightly alkaline pH, it is very tolerant and adapts well to dry, sandy, and acidic soil. A light application of slow-release fertilizer in spring will keep it growing well.
Plants are readily available at nurseries in spring, or if you know someone who has it growing in their garden, it can be easily shared. Most gardeners are happy to dig a shovelful with roots attached from the edge of a clump. If the clump is too young or too small to be divided, ask for a few cuttings, for they are easily rooted.
Once established very little care is needed. Plants can invigorated and lush new growth encouraged by cutting back by about one-third to halfway immediately after flowering. Dividing the clumps every three or four years will help to keep them vigorous. Each spring moss phlox appreciates a light application of fertilizer to the soil. During dry weather, water early in the morning until the soil is damp three to four inches deep. Early morning watering allows the plants the longest possible drying time and helps to prevent mildew and rot. Spider mites may attack during hot, dry weather. Treat if necessary.
While these maintenance practices may be needed in a highly visible place in the garden, moss phlox can last for years in thin, sandy or poor soil where the sun beats down relentlessly during the summer and the cold of winter covers it with snow. It may not be as vigorous and showy as it is in a well-tended garden, but that, in itself, may be the key to its longevity.
In the Garden
Use moss phlox at the edge of a border. Its small stature and spreading and draping habit make it a great selection for the top of a wall or in a container where it can cascade down the sides. In rock gardens, these same qualities make it an effective choice since it creeps over rocks and weaves its way among them quite easily.
Choose from many selections of Phlox subulata. At nurseries they may simply be identified by the names of the colors, which may be shades of white, lavender, pink, rose, and red. Specific cultivars include 'Atropurpurea', ‘Emerald Blue', ‘Snowflake', ‘Red Wings', ‘Chattahochee', and many others. See several examples of specific colors and cultivars on Dave's Garden.
Florescent pink is the most commonly seen color of moss phlox. Try some of the more refined colors if you wish. Although I have tried many of the more subtly colored types, this loud pink phlox performs best in my garden. I might tire of it if it lasted all year, but for a couple of weeks in spring it is delightful.
At a Glance
Pronunciation: floks sub-yoo-LAY-tuh
Family: Polemoniaceae (Phlox family)
Common names: moss phlox, creeping phlox, ground pink, thrift, moss pink
Origin: Eastern U.S.A.
Hardiness: USDA Zones 3-9
Size: 3-6 inches tall by 18-24 inches diameter
Thanks to Todd Boland for the use of his images which are identified with the Dave's Garden copyright.