Phlox subulata
Phlox subulata is a low, mat‑forming perennial that creates a spring carpet of color on slopes, walls, and sunny edges. One trait that stands out is its dense evergreen mat that controls erosion on banks. It is best where winters are cold and springs are bright, and it tolerates lean, sandy or gravelly soils. Plants bloom most heavily in full sun and appreciate sharp drainage in humid climates. This species is durable in heat once established and needs little care beyond a post‑bloom trim.
At‑a‑glance
- Group/Class: Herbaceous perennial ground cover (moss phlox)
- Height × spread: 3–6 in (8–15 cm) × 12–24 in (30–60 cm)
- Bloom window: March to May
- Color & flower form: Loose clusters of small, notched, star‑shaped flowers in pink, purple, or white
- Fragrance: 1 trace
- USDA hardiness: zones 3–9
- Breeder / Year / Origin: unknown; native to eastern and central United States
- Pet safety: safe
How it differs
- Forms a tight evergreen mat rather than upright clumps.
- Very early spring bloom rather than midsummer.
- Better drought tolerance after establishment.
- Less susceptible to powdery mildew than tall garden phlox.
Strengths
- Early season color.
- Handles slopes and rocky sites.
- Low maintenance after establishment.
- Attracts pollinating insects.
Care in one minute
- Plant in full sun with excellent drainage; sandy or gravelly soil is ideal.
- Water to establish; afterward, water during prolonged drought only.
- Shear lightly after bloom to keep a dense mat and encourage rebloom.
- Fertilize sparingly; too much nitrogen reduces flowering.
- Divide or replant edges when mats thin in the center.
Watch‑outs
- Spider mites may appear in hot, dry spells.
- Foliar nematodes can damage leaves in wet weather.
- Rabbits may nibble young growth.
Best uses (tags)
slopes; rock gardens; edging; pollinators; ground cover
Provenance note
Native to dry, rocky sites of the eastern United States; widely planted in rock gardens for more than a century.
References
- Missouri Botanical Garden – Phlox subulata
- NC State Extension – Phlox subulata
- Morton Arboretum – Moss phlox
- ASPCA – Moss Phlox (non‑toxic)
Written by: Your Flowers Guide editorial team
We are a small independent group of flower lovers who research and review each guide using trusted horticultural and educational sources. Learn more about us