How to Grow Cushion Phlox
Wikimedia Commons
Cushion Phlox
Phlox subulata
flowerCushion phlox is a low-growing, mat-forming perennial ground cover that blooms profusely with small, five-petaled flowers in spring. It typically reaches only 4-6 inches in height and spreads 12-18 inches, making it ideal for rock gardens, borders, and alpine areas. The needle-like foliage remains attractive even after flowering season ends.
Looking for a specific variety?
When should you plant Cushion Phlox in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Cushion Phlox timeline · Pittsburgh, PA (Zone 6b)
-
Plant Cushion Phlox
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
First Cushion Phlox blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Cushion Phlox dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9, with best performance in zones 4-8
Sign up free to see if Cushion Phlox grows in your zone — and get a personalized planting timeline.
Get my Cushion Phlox timeline →Growth Stages
Seedling/Transplant
4-8 weeksYoung plants develop needle-like foliage in tight rosettes; very compact growth habit begins to establish.
Keep soil consistently moist but not waterlogged during establishment. Provide bright light. Space transplants 12 inches apart.
Vegetative Growth
Spring through early summerMat expands laterally as stems root along the soil, creating a dense carpet. Foliage remains evergreen and needle-like; plant gains height only to 4-6 inches.
Water regularly until roots establish. Once rooted, reduce watering frequency. Thin crowded stems if needed. No fertilizer required; excessive nitrogen reduces flowering.
Budding/Flowering
4-6 weeks (typically April-May)Numerous small flower buds form at stem tips, opening into five-petaled blooms in pink, white, red, lavender, or bicolor varieties. Entire mat becomes a blanket of color.
Provide full sun for best bloom. Deadhead spent flowers to encourage prolonged blooming. Reduce watering during peak blooms.
Post-Bloom & Summer Dormancy
June-AugustFlowers fade; foliage becomes the main attraction. Plant enters semi-dormant period in heat. Evergreen cushion remains attractive.
Do not fertilize. Water only during extreme drought. Avoid overhead watering. Ensure excellent drainage to prevent fungal issues in humidity.
Hardening Off/Fall & Winter
September-MarchFoliage may deepen in color with cooler temperatures. Plant remains evergreen but growth slows dramatically. Appears dormant but remains alive.
No watering needed unless fall is exceptionally dry. Ensure good drainage for winter wet periods. Mulch lightly if winters are harsh (zone 3-4).
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
-
Spray with water to dislodge; use insecticidal soap if severe. Improve air circulation.
-
Reduce overhead watering; ensure good air circulation. Apply sulfur dust or fungicide if needed. Avoid humid conditions.
-
and
Remove by hand, especially in damp conditions. Apply copper tape barriers. Beer traps around plants.
-
Improve drainage; reduce watering frequency. Do not mulch heavily around base. Remove affected plants if widespread.
Uses
Edible garnish
CulinaryThe small flowers are edible and can be used as a delicate, slightly sweet garnish for desserts and salads. However, cushion phlox is primarily grown ornamentally rather than for culinary purposes. [source]
Ground cover and erosion control
HouseholdExcellent for covering bare ground, stabilizing slopes, and filling crevices in rock gardens. Its dense mat-forming habit prevents soil erosion and suppresses weeds effectively. [source]
Cut flowers and floral arrangements
CraftSmall stems and flower sprays can be used in miniature floral arrangements and pressed flower crafts. The tiny flowers dry well and retain color for preservation projects. [source]
Pollinator nectar source
WildlifeSpring blooms attract butterflies, bees, and other pollinating insects during early-season flowering when nectar sources are scarce. Supports ecological diversity in gardens. [source]
Alpine and rock garden staple
HouseholdIdeal for creating colorful tapestries in rock gardens, troughs, and alpine plantings. Low maintenance and drought-tolerant once established, making it perfect for xeriscaping and water-wise landscapes. [source]
Harvest Tips
Cushion phlox is an ornamental flower; no harvesting for food. Cut stems for fresh arrangements during peak bloom if desired, though flowers are small. Harvest seeds in late summer by collecting dried seed pods before they shatter; allow to dry indoors, then collect and store in cool, dry location for spring sowing.
Fun Facts
- 🌱 Cushion phlox 'Moss Pink' earned its nickname because its needle-like foliage resembles moss when not in bloom—creating a two-season display.
- 🌱 It is one of the hardiest phlox species and can survive extreme cold; some cultivars are reliably winter-hardy to zone 2.
- 🌱 The flowers open in sequence from the base of the stem upward, extending the bloom period over several weeks and ensuring continuous color.
Gardening Terms
New to gardening? Learn about terms used in this guide:
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Cushion Phlox planting timeline
Tell us your zip code and we'll calculate exactly when to start Cushion Phlox seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Cushion Phlox timeline →