Creeping phlox (Phlox stolonifera) is a low-growing, mat-forming plant that is often seen spreading as a ground cover, in rock gardens, and even in crevices of stone walls. It blooms in the late spring to early summer with clusters of fragrant, five-petal flowers that stretch almost an inch across. These flowers tend to attract butterflies and other pollinators to a garden. And after they’re done blooming, the creeping phlox foliage still remains green and attractive for much of the year before dying back in the winter. Plant your creeping phlox in the spring after the danger of frost has passed. The plant has a moderate growth rate.
|Botanical Name||Phlox stolonifera|
|Common Names||Creeping phlox, moss phlox, star rock phlox|
|Plant Type||Herbaceous, perennial|
|Mature Size||6-12 in. tall, 9-18 in. wide|
|Sun Exposure||Full, partial|
|Soil Type||Loamy, well-drained|
|Soil pH||Acidic, neutral, alkaline|
|Bloom Time||Spring, summer|
|Flower Color||Purple, pink, white|
|Hardiness Zones||5-9 (USDA)|
|Native Area||North America|
Creeping Phlox Care
Creeping phlox is a fairly low-maintenance plant. It requires watering if you have a week or two without rainfall, along with an annual feeding. Plus, mature plants might need a bit of pruning maintenance to keep them looking tidy unless you'd like for your phlox to naturally spread and blanket a large area.
As with many ground covers, grass and weeds growing up through the phlox can be a nuisance. And they will compete with your phlox for soil nutrients and moisture. It's best to start managing weeds early in the spring before the phlox blooms and its foliage is at its fullest. Hand-pulling is the most effective method for removing weeds, and it means you won't have to use any hazardous weed killers around yourself or the phlox. If you let the weeds get out of control, it might be easiest to dig up the phlox (keeping its roots intact), clear the area of grass and weeds, and then replant the phlox.
This plant grows best in full sun to partial shade. Too much shade can impede flower production.
Creeping phlox likes soil that is rich in organic matter. It prefers a slightly acidic soil pH but also can tolerate neutral and slightly alkaline soil. Moreover, it needs a well-drained soil.
This plant requires a moderate amount of soil moisture, though mature plants do have some drought tolerance. Unless you have rainfall, it will generally need watering weekly, especially during the heat of the summer.
Temperature and Humidity
Creeping phlox plants are fairly hardy in their growing zones. They tolerate heat well and can handle some frost, though prolonged exposure to temperatures below 40 degrees Fahrenheit can damage the plants. Moreover, humidity is typically not an issue for the plants.
Fertilizing in the late winter or early spring will promote growth and support a more robust bloom for your creeping phlox. Feed it with a general slow-release fertilizer suitable for flowering plants.
Varieties of Creeping Phlox
There are many varieties of creeping phlox, including:
- Phlox stolonifera ‘Fran’s Purple’: This phlox features deep green leaves and rich purple flowers.
- Phlox stolonifera ‘Home Fires’: This plant sports bright pink flowers.
- Phlox stolonifera ‘Pink Ridge’: This variety has flowers that are similar in color to ‘Home Fires’.
- Phlox stolonifera ‘Sherwood Purple’: This plant features blue-purple flowers.
Pruning is optional on these plants. After the blooming period is over, you can trim back the foliage to create a neater form. This also will promote denser foliage, enhancing the phlox's beauty as a ground cover. Alternatively, you can skip the pruning and let the plants grow naturally. Plus, you do not need to deadhead these plants (remove the spent blooms), though in some cases this can result in a second bloom.
Propagating Creeping Phlox
To propagate creeping phlox plants, simply divide your plants in the spring immediately after they are finished blooming. Dig up the entire plant, including the root ball. Cut through the roots to divide the plant roughly in half, and then replant each half wherever you wish. Typically, you can divide a plant every two to three years without seriously weakening it.
Creeping phlox is less susceptible to the powdery mildew that plagues other phlox species, but spider mites can be an issue is hot, dry climates. Insecticidal soaps are often helpful for this problem. Another option is to spray the plants regularly with a hard stream of water to dislodge the mites and keep them under control.
These plants also can be susceptible to foliar nematodes in wet, humid weather. Nematodes cause lesions on the leaves of the plants that turn brown and then black. These soil organisms are hard to control. So diseased plants must be removed and destroyed, and the ground should be kept clean of debris.