Creeping Phlox (Phlox subulata): How to Grow and Care for It

Creeping phlox is one of the great sights of spring. For a few weeks, usually in April and May, its low mats of needle-like leaves disappear under a carpet of small, starry flowers in pink, magenta, lavender-blue, white and red, spilling over walls, covering slopes and edging paths so thickly that the foliage underneath is hidden. For the rest of the year, it forms a tidy, evergreen, moss-like cushion that holds soil in place and keeps weeds down.

Creeping phlox is native to the eastern and central United States, where it grows on rocky ledges, slopes and sandy clearings. That background tells you exactly what it wants: sun, sharp drainage and not much fuss. Give it those, and it is one of the easiest, longest-lived groundcovers you can grow.

Creeping Phlox Quick Facts

Botanical name	Phlox subulata
Common names	Creeping phlox, moss phlox, moss pink, mountain pink
USDA zones	3 to 9
Sun	Full sun; tolerates light part shade
Height	3 to 6 inches
Spread	1 to 2 feet
Bloom time	Early to late spring, depending on climate
Grown for	Both flowers and evergreen foliage
Flower color	Pink, magenta, lavender-blue, white, red, striped
Soil moisture	Dry to average, well drained
Deer	Sometimes browsed
Drought tolerance	High once established
Native range	Eastern and central United States
Pet toxicity	Not known to be toxic
Maintenance	Low

What Is Creeping Phlox?

Creeping phlox, Phlox subulata, is a low, spreading perennial that grows only 3 to 6 inches tall but can spread 2 feet or more. Its species name, subulata, is Latin for awl-shaped, a reference to its stiff, narrow, needle-like leaves. The stems trail along the ground and root where they touch the soil, gradually knitting into a dense mat. The foliage stays green through winter in most climates, which is why it is often called moss phlox.

The common names can be confusing. Some nurseries also use the name creeping phlox for Phlox stolonifera, a different native species that spreads by runners and prefers shade and moist, rich soil. Woodland phlox (Phlox divaricata) is another spring bloomer for shade. This guide covers Phlox subulata, the sun-loving groundcover with needle-like leaves. It is a close relative of tall garden phlox (Phlox paniculata), which blooms in summer.

Where Creeping Phlox Grows Best

Creeping phlox is hardy in USDA zones 3 through 9, from the northern Plains and New England to the Gulf Coast. It blooms as early as February in the Deep South and in April and May farther north.

Give it full sun, at least 6 hours of direct light a day, for the densest growth and heaviest bloom. It tolerates light shade, but in too much shade the mats become thin and open and flower poorly.

Drainage is the key. Creeping phlox thrives in sandy, gravelly, rocky or even poor soil, and tolerates dry sites, slopes and the heat reflected from pavement and walls. The University of Maryland Extension lists a suitable pH range of about 5.7 to 7.5, and the plant tolerates slightly alkaline soil. It struggles in heavy clay and soil that stays wet, especially in winter, when the crowns and roots can rot.

How to Plant Creeping Phlox

Plant creeping phlox in spring or early fall, at least six weeks before the ground freezes. Loosen the soil and, if it is heavy, mix in coarse sand or fine gravel to improve drainage rather than rich compost. Set each plant so the top of the root ball is level with the soil surface, backfill and water well.

Space plants 12 to 18 inches apart for a solid groundcover in two or three seasons, or closer for faster coverage. On slopes, stagger the plants in a checkerboard pattern so they knit together and hold the soil. Mulch lightly with fine gravel or leave the soil bare around new plants; heavy wood mulch holds moisture against the stems and slows their spread.

Watering and Feeding

Water new plants about once a week through their first season if rain is scarce. Once established, creeping phlox is very drought tolerant and rarely needs watering except in long, hot dry spells. Overwatering and soggy soil cause far more problems than drought.

Creeping phlox needs little or no fertilizer. In very poor soil, a light sprinkle of compost or a balanced slow-release fertilizer in early spring is plenty. Too much fertilizer produces loose, leggy growth with fewer flowers.

Pruning and Shearing Creeping Phlox

Creeping phlox needs only one trim a year. After the flowers fade in late spring, shear the mats back by about a third to a half with hedge shears or scissors. This removes the spent flowers, keeps the plants dense and compact and encourages fresh growth that will carry next spring’s flowers. The University of Maryland Extension notes that shearing sometimes brings a light second flush of flowers.

Do the shearing soon after bloom, since creeping phlox sets its flower buds for the following spring during summer and fall. Do not cut the plants back in fall. The evergreen foliage protects the crowns over winter, and cutting it removes next year’s flowers. In early spring, simply trim out any stems that were killed or browned by winter.

Dividing and Propagating Creeping Phlox

Older mats sometimes thin out or die in the center while the edges keep spreading. Every three to four years, or whenever a planting starts to look patchy, divide it in spring after flowering or in early fall. Dig up sections of the mat, cut them into pieces with healthy stems and roots and replant them at the same depth, filling in any bare spots.

Creeping phlox is also easy to propagate. Stems that have rooted where they touch the soil can simply be cut from the parent plant and replanted. You can also take 3- to 4-inch cuttings from new growth in late spring or summer and root them in moist, gritty potting mix.

Winter Care

Creeping phlox is very cold hardy and needs little winter protection. In exposed spots without reliable snow cover, the evergreen foliage can brown from winter sun and wind. A loose covering of evergreen boughs after the ground freezes helps in the coldest zones. Avoid piling leaves or heavy mulch on the mats, which can smother them and cause rot. Browned foliage usually greens up or is replaced by new growth in spring.

Best Creeping Phlox Varieties

There are dozens of named varieties of creeping phlox, differing mainly in flower color and size. These are widely available and reliable.

‘Emerald Blue’

One of the most popular varieties, with soft lavender-blue flowers over especially dense, bright green foliage. It is vigorous and spreads well on slopes and walls.

‘Emerald Pink’

A companion to ‘Emerald Blue’ with bright pink flowers and the same dense, healthy mat of foliage.

‘Snowflake’

A pure white variety with a compact, tight habit. White creeping phlox brightens rock gardens and pairs well with pink and blue varieties.

‘Drummond’s Pink’

A variety with deep pink flowers that are larger than those of most creeping phlox, making a bold carpet of color in spring.

‘Amazing Grace’

White flowers marked with a pink to raspberry eye, on a low, compact mat. Its two-toned flowers are especially attractive up close along paths and in containers.

‘Candy Stripe’

Pink and white striped flowers that give a softer, lighter effect from a distance. It is a good choice for mixing with solid colors.

Creeping Phlox for Pollinators

Because it blooms so early, creeping phlox is an important nectar source for early-season pollinators. Bees, skippers and early butterflies visit the flowers in spring, when few other plants are blooming. Planting it alongside other early perennials, such as columbine, rock cress and spring bulbs, creates a valuable early buffet for pollinators.

How to Use Creeping Phlox in the Garden

Creeping phlox is one of the most versatile groundcovers for sunny spots. Plant it along the edges of walkways, driveways and patios, where its mounds can spill over the edge. Let it cascade over retaining walls and stone steps, or tuck it into rock gardens and between large stones. On sunny slopes, it helps control erosion while providing a sheet of spring color. It also combines well with spring bulbs such as daffodils, tulips and grape hyacinths, whose foliage it helps hide as it fades.

Companion Plants for Creeping Phlox

Creeping phlox pairs well with other sun-loving, low-growing plants that like good drainage. Candytuft, rock cress, basket-of-gold and creeping thyme bloom at the same time and share its needs. Sedum, dianthus and hens and chicks provide interest after the phlox has finished blooming. Taller plants such as catmint, lavender and salvia make good neighbors behind it, extending the season into summer.

Common Creeping Phlox Problems

Creeping phlox has few serious problems, and most are caused by wet soil or too much shade.

Dying or Brown Patches

Patches that brown or die out in the middle of a mat are usually caused by wet soil, heavy mulch or old, woody growth. Improve drainage, pull back mulch and divide and replant healthy sections to fill the gap.

Spider Mites

Spider mites occasionally attack creeping phlox in hot, dry weather, causing fine yellow speckling and a dull, bronzed look. A strong spray of water or insecticidal soap controls them, and keeping plants from becoming drought stressed helps prevent them.

Powdery Mildew and Root Rot

Powdery mildew is much less of a problem on creeping phlox than on garden phlox, but it can appear in humid weather. Root and crown rot occur in poorly drained soil. Good drainage and full sun prevent both.

Deer and Rabbits

Creeping phlox tolerates occasional browsing by deer, and rabbits sometimes nibble the foliage. The plants usually recover, but in areas with heavy pressure a repellent may be needed while plants are establishing.

Growing Creeping Phlox in Containers

Creeping phlox looks beautiful spilling over the edges of containers, window boxes and troughs. Use a pot with drainage holes and a gritty, well-draining mix, such as potting mix blended with coarse sand or perlite. Place it in full sun and water when the top inch of mix is dry. In zones colder than 5, move pots to a sheltered spot for winter or plant them in the garden in fall.

Frequently Asked Questions

These are the questions gardeners ask most about creeping phlox.

Does Creeping Phlox Spread?

Yes. Creeping phlox spreads by trailing stems that root where they touch the soil, gradually forming mats 2 feet or more across. It spreads steadily but is not invasive and is easy to control.

Is Creeping Phlox Evergreen?

Yes, in most climates. The needle-like foliage stays green through winter, although it can brown in exposed spots without snow cover and usually recovers in spring.

Should You Cut Back Creeping Phlox?

Yes, once a year right after it finishes blooming in late spring. Shear it back by a third to a half to keep it dense. Do not cut it back in fall, since that removes next spring’s flower buds.

How Long Does Creeping Phlox Bloom?

Creeping phlox blooms for about three to four weeks in spring, sometimes with a light second flush after shearing.

Can Creeping Phlox Grow in Shade?

It tolerates light shade but blooms best in full sun. For shady spots, the native Phlox stolonifera and woodland phlox are better choices.

Is Creeping Phlox Deer Resistant?

Only partly. Deer usually pass it by for other plants, but they browse it occasionally, especially in early spring when little else is green. Established mats recover quickly from light browsing.

When Should You Plant Creeping Phlox?

Plant creeping phlox in spring, after the soil can be worked, or in early fall at least six weeks before the ground freezes. Potted plants in bloom can be planted in spring and will settle in quickly with regular watering.