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How to Grow Scarlet Flame Moss Phlox

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Scarlet Flame Moss Phlox

Phlox subulata 'Scarlet Flame'

flower

Scarlet Flame Moss Phlox is a low-growing, creeping ground cover known for its vibrant scarlet-red flowers that blanket the plant in spring. It features needle-like foliage and spreads to create dense mats, making it ideal for rock gardens, borders, and containers. This cultivar is a hardy perennial that thrives in well-drained soils and sunny locations.

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Example Scarlet Flame Moss Phlox timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Scarlet Flame Moss Phlox

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Scarlet Flame Moss Phlox blooms

    Mid-to-late summer

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Scarlet Flame Moss Phlox dates for your own zip code.

Growing Conditions

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Sun: Full sun, 6-8 hours daily; tolerates light afternoon shade in hot climates
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Water: Low water needs once established; water moderately during growing season; drought-tolerant; avoid overwatering which causes root rot
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Spacing: 12 inches
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Days to maturity: Blooms in 8-12 weeks from transplant; reaches mature spread in 1-2 years
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Planting depth: Plant at same depth as container; seeds barely covered (1/8 inch)

Soil

Type: Well-draining sandy or gravelly soil
pH: 6.0-7.0
Amendments:
Perlite or coarse sand for drainage Gravel mulch Avoid heavy clay or organic-rich soils

Growing Zones

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Thrives in zones 3-8; cold-hardy and excellent for northern gardens

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b

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Growth Stages

1

Seedling

2-3 weeks

Tiny needle-like leaves emerge; very delicate appearance

Keep soil lightly moist; provide bright light; do not overwater

2

Vegetative Growth

4-8 weeks

Plant develops a dense mat of fine, linear foliage; spreads horizontally

Water moderately; ensure excellent drainage; do not fertilize heavily

3

Budding

2-3 weeks

Small buds appear at stem tips, clustered together

Reduce watering slightly; maintain full sun exposure

4

Flowering

3-6 weeks (spring, typically April-May)

Brilliant scarlet-red flowers open in dense clusters covering the foliage; peak bloom

Deadhead spent flowers to encourage continued blooming; avoid overwatering

5

Post-Bloom

Summer dormancy, 6-8 weeks

Flowers fade; plant may rebloom lightly in fall with cooler temperatures

Light deadheading encourages fall bloom; reduce watering as plant enters dormancy

Companion Planting

Plan your garden →

Plant with:

Creeping Thyme Sedum Creeping Phlox other varieties Candytuft Armeria Alpine Phlox Lamb's Ear Germander

Avoid planting near:

Plants requiring frequent watering Shade-loving plants Heavy feeders Dense shrubs that compete for space

Common Pests

  • Spray with water; use miticide if severe; ensure good air circulation

  • Improve air circulation; apply sulfur dust or fungicide; avoid overhead watering

  • Ensure excellent drainage; avoid overwatering; remove affected plants

  • and

    Remove by hand; copper tape barriers; beer traps; diatomaceous earth

Uses

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Rock Gardens and Alpine Displays

Ornamental

Scarlet Flame Moss Phlox excels as a vibrant accent in rock gardens, alpine troughs, and scree gardens. Its low growth habit and brilliant color make it perfect for front-of-border plantings. [source]

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Ground Cover and Erosion Control

Ornamental

Creates dense, attractive mats that suppress weeds and prevent soil erosion on slopes and banks. Spreads 12-18 inches wide and provides year-round green foliage. [source]

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Pollinator Attraction

Wildlife

Attracts bees, butterflies, and hummingbirds during its spring blooming period. Provides early-season nectar and pollen when many pollinators emerge. [source]

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Container and Edging Gardens

Ornamental

Ideal for containers, hanging baskets, and pathway edging where its cascading habit and brilliant blooms create striking visual impact. Works well in tufa troughs and garden containers. [source]

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Cottage Garden Design

Ornamental

Classic component of traditional cottage gardens and borders; provides early spring color alongside bulbs and spring perennials. Its low maintenance nature makes it popular for naturalized plantings. [source]

Harvest Tips

Moss Phlox is not harvested for food or material; deadhead spent flowers by pinching or cutting spent flower clusters to encourage continued blooming throughout spring. Cut back after flowering season ends to maintain compact growth.

Fun Facts

  • 🌱 The common name 'Moss Phlox' refers to its fine, needle-like foliage that resembles moss in texture and appearance.
  • 🌱 Phlox subulata is one of the hardiest phlox species and can survive temperatures well below -20°F, making it invaluable for northern gardens.
  • 🌱 Despite its delicate appearance, Scarlet Flame Moss Phlox is remarkably drought-tolerant once established and actually prefers lean, well-drained soils to rich garden soil.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Cultivar Deadhead Full Sun Perennial pH
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