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Phlox /flɔks/

Common name: Phlox · Moss phlox · Creeping phlox · Garden phlox

Phlox is a genus of about 70 species of perennial and annual flowering plants in the Polemoniaceae family, nearly all native to North America. Rock-garden species such as Phlox subulata (moss phlox) form dense, creeping evergreen mats smothered in pink, purple, blue, or white flowers in spring, while taller border species like Phlox paniculata carry fragrant summer flower heads on upright stems. Gardeners grow phlox as ground covers, rock-garden subjects, and pollinator-friendly border perennials. The name comes from the Greek word for flame, a nod to the vivid flower colors.

Care summary

Sun Full sun for creeping types; light shade tolerated by woodland species
Water Water during dry spells; keep soil lightly moist, not soggy
Soil Well-drained, moderately fertile soil; creeping species prefer gritty, sharply drained, leaner mixes
Hardiness Zones 3–9
Mature height 5–15 cm (2–6 in) for creeping mats; up to 120 cm (4 ft) for tall border species
Pet safe Generally considered non-toxic to cats and dogs (ASPCA-listed for moss phlox)
Propagation By division, stem or basal cuttings, or seed

Fun facts

  • The genus name Phlox comes from the Greek word for flame, referring to the intense flower colors.
  • Moss phlox (Phlox subulata) can bloom so heavily in spring that its needle-like foliage disappears completely under flowers.
  • Phlox drummondii, the annual phlox, is the state wildflower of Texas in all but name, carpeting roadsides there each spring.
  • Butterflies and hummingbird moths are major pollinators of phlox, drawn to the nectar held in its narrow flower tubes.

Common problems

    • Space plants for good air circulation
    • Water at base, not overhead
    • Remove and discard affected leaves
    • Choose mildew-resistant cultivars
    • Hose plants with firm water spray
    • Keep soil evenly moist
    • Plant in sharply drained soil
    • Avoid winter watering of dormant clumps
    • Raise beds to shed winter rain
    • Dig out and discard rotted clumps
    • Divide clumps every few years
    • Replant vigorous outer sections
    • Discard the woody dead center
    • Cut back after flowering to renew growth