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Phlox subulata /flɔks/

Common name: Moss phlox · Creeping phlox · Moss pink · Mountain phlox

Phlox subulata is a low, mat-forming evergreen perennial native to eastern North America, from the Appalachians and the eastern United States into adjacent Canada. Its dense, moss-like carpets of narrow, awl-shaped leaves are blanketed in spring by masses of starry, five-petaled flowers in shades of pink, purple, lavender-blue, and white. It is one of the most popular groundcovers for rock gardens, slopes, walls, and sunny borders, valued for erosion control and its spectacular spring display.

Care summary

Sun Full sun; tolerates light shade
Water Drought tolerant once established; water during prolonged dry spells
Soil Well-drained, sandy or gritty soil; dislikes wet, heavy clay
Hardiness Zones 3–9
Mature height 10–15 cm (4–6 in)
Pet safe Non-toxic to cats, dogs, and horses per the ASPCA
Difficulty Easy
Propagation By stem cuttings after flowering or division in spring

Fun facts

  • The epithet 'subulata' means awl-shaped, referring to the stiff, needle-like leaves that give the mats their moss-like look.
  • In peak bloom the flowers can cover the foliage so completely that the planting reads as a solid sheet of color.
  • The mats stay evergreen (or semi-evergreen) through winter, often taking on bronze or purplish tones in cold weather.
  • The nectar-rich spring flowers are an early food source for butterflies, bees, and hummingbird moths.

Common problems

    • Grow in gritty, fast-draining soil
    • Site in full sun on a slope
    • Keep mulch away from crowns
    • Remove and bin rotting sections
    • Hose plants with firm water spray
    • Keep soil evenly moist
    • Lift and divide mats in early autumn
    • Replant healthy rooted outer shoots
    • Cut out dead central growth
    • Shear lightly after flowering
    • Move to full sun
    • Cut back shading overhanging branches
    • Avoid high-nitrogen feeding