How to Grow Moss campion

iNaturalist

Moss campion

Silene acaulis

flower

Moss campion is a cushion-forming alpine plant that creates dense, moss-like mounds of tiny evergreen leaves topped with delicate pink or red flowers. Native to high mountain regions and Arctic tundra, this slow-growing perennial is prized by rock gardeners for its compact habit and charming blooms. It thrives in harsh, well-drained conditions where few other plants can survive.

When should you plant Moss campion in your zone?

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Example Moss campion timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Moss campion

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Moss campion blooms

    Mid-to-late summer

    Before the first fall frost (≈ Nov 8)

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

Growing Conditions

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Sun: Full sun, 6+ hours daily; tolerates partial shade in very hot climates
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Water: Low to moderate; water sparingly once established. Keep moist during growing season but never waterlogged. Drought-tolerant once mature. Reduce watering in winter.
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Spacing: 12-18 inches
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Days to maturity: Not applicable; ornamental perennial that blooms in 2-3 years from seed
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Planting depth: Surface sow or barely cover seeds; they need light to germinate

Soil

Type: Very well-draining sandy or gravelly soil; gritty alpine soil preferred
pH: 6.0-7.0
Amendments:
Coarse sand fine gravel perlite peat moss in small amounts

Growing Zones

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Thrives in zones 2-6; best in cooler alpine and subarctic regions

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b

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Growth Stages

1

Seed germination

3-4 weeks

Tiny seeds require cold stratification and light; very slow germination over 3-4 weeks

Stratify seeds 4-6 weeks in moist sand at 3-5°C. Sow on surface of gritty mix. Keep lightly moist, provide bright light. Germination is slow and sporadic.

2

Seedling & juvenile

6-12 months

Tiny seedlings develop very slowly, forming first few leaves and establishing root system

Transplant to well-draining pots when large enough to handle. Keep in cool conditions. Reduce watering frequency. Grow in bright light without heat. Very slow process.

3

Cushion formation

1-2 years

Plant gradually forms characteristic dense, rounded moss-like cushion of tiny evergreen leaves

Maintain excellent drainage and cool temperatures. Minimal fertilizer needed. Avoid disturbance. Growth rate is 1-2 inches per year. Patience is essential.

4

Flowering

4-8 weeks (May-July)

Tiny pink, rose, or rarely white flowers appear in late spring to early summer, covering the cushion surface

Blooming typically begins in 2-3 years from seed. Provide full sun for best flowering. Continue careful watering and drainage. Flowers last several weeks.

5

Seed production & dormancy

Continuous after establishment

After flowering, plant sets seed and enters dormancy, remaining evergreen throughout winter

Allow seed to mature if desired for collection or self-seeding. Keep plant dry in winter. Protect from excessive moisture and poor drainage. Mulch lightly with fine gravel, not organic matter.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Moisture-loving plants Tall shade-casting plants Aggressive spreading perennials Humid lowland plants

Common Pests

  • Spray with water or insecticidal soap; encourage beneficial insects in alpine rock gardens

  • Rare but possible in dry conditions; spray with water; maintain adequate moisture

  • Prevent with impeccable drainage; never overwater; remove affected plants immediately

  • Remove by hand; use copper barriers or slug bait if necessary; improve drainage to reduce slugs

Uses

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Alpine rock garden centerpiece

Craft

Moss campion is a classic alpine garden plant prized for creating living cushions in rock gardens, troughs, and scree beds. Its slow growth and architectural form make it ideal for small-scale landscaping. [source]

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Pollinator nectar source

Wildlife

The small but numerous flowers attract alpine bees, butterflies, and other pollinators in mountain and arctic habitats. A key nectar source in harsh environments. [source]

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Traditional herbal medicine

Medicinal

In traditional medicine systems of Arctic and alpine regions, Silene acaulis has been used in infusions for respiratory ailments and general vitality, though scientific evidence is limited. [source]

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Drought-tolerant landscaping

Household

An excellent plant for xeriscaping and water-wise gardens in cold climates. Requires virtually no supplemental watering once established. [source]

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Trough and container gardens

Craft

Perfect for hypertufa troughs, alpine pans, and container plantings where excellent drainage can be maintained. Adds fine texture and delicate color. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Moss campion is not harvested for consumption. For seed collection, allow flowers to fade and seed pods to dry on the plant in late summer. Collect papery seed capsules and allow to dry further indoors. Seeds are tiny and difficult to handle; store in cool, dry conditions.

Fun Facts

  • 🌱 Moss campion is one of the slowest-growing plants in the world, expanding at a rate of only 1-2 inches per year. A mature cushion may be over 100 years old yet only 3-4 inches across.
  • 🌱 This plant forms extremely dense cushions—up to 100 times denser than comparable lowland plants—as an adaptation to harsh alpine winds and low temperatures that can drop to -40°C.
  • 🌱 Moss campion creates its own microclimate: surface temperatures within the cushion can be 15°C warmer than the surrounding air, allowing flowers to thrive in arctic conditions where the air temperature may remain near freezing.

Gardening Terms

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