How To Grow Snow-in-Summer

RECOMMENDED USDA GROWING ZONES: 3–7

Snow-in-Summer (Cerastium tomentosum) is a hardy perennial groundcover known for its soft, silvery-gray foliage and abundant, star-shaped white flowers. During late spring and early summer, established plants can become covered in blossoms, creating the appearance of a blanket of snow.

Plants typically form dense foliage mats approximately 4–6 inches tall, with flowering stems reaching 8–12 inches. Snow-in-Summer is especially well suited to sunny slopes, rock gardens, and borders with excellent drainage.

STEP 1 — CHOOSE A SUNNY, WELL-DRAINED LOCATION

Select a planting area receiving at least 6 hours of direct sunlight daily.

Snow-in-Summer grows best in sandy, rocky, or moderately poor soil that drains quickly. Rich soil and excessive moisture can encourage weak growth or root rot.

Avoid low-lying areas where water collects after rain. Raised beds and sloped planting areas are particularly suitable.

This perennial performs best in regions with relatively cool summers. Prolonged heat and high humidity may cause foliage decline, even within its recommended hardiness range.

STEP 2 — SOW THE SEEDS

NO COLD STRATIFICATION IS NORMALLY REQUIRED.

Snow-in-Summer seeds are small and should be sown on the soil surface, where they receive light during germination.

STARTING INDOORS:

1. Begin approximately 6–8 weeks before your last expected spring frost.
2. Fill seed trays with a lightly moistened, well-drained seed-starting mix.
3. Scatter seeds thinly over the surface and press them gently into the mix. Do not bury them.
4. Keep the trays in bright, indirect light at approximately 65–75°F (18–24°C).
5. Mist gently as needed to maintain consistent surface moisture without waterlogging the soil.

Germination generally takes approximately 14–30 days under suitable conditions.

DIRECT OUTDOOR SOWING:

Sow in spring after severe freezing conditions have passed, or in early fall where sufficient time remains for seedlings to establish before winter.

Prepare a fine, weed-free seedbed, press seeds onto the surface, and water carefully. Keep the surface lightly moist until seedlings develop.

STEP 3 — THIN AND TRANSPLANT SEEDLINGS

Once seedlings develop several true leaves and are large enough to handle, thin or transplant them to approximately 12–18 inches apart.

For seedlings started indoors, gradually introduce them to outdoor sunlight and temperatures over 7–10 days before transplanting.

Plant at the same depth they occupied in their original containers, taking care not to damage the developing roots.

Water thoroughly after transplanting and continue providing light, regular moisture while plants establish.

Young plants initially grow as small silvery rosettes before gradually spreading into interconnected mats.

STEP 4 — WATER AND MAINTAIN ESTABLISHED PLANTS

Once established, Snow-in-Summer is relatively drought-tolerant and generally needs less supplemental watering than many other flowering groundcovers.

Allow the upper soil to dry between waterings. During prolonged drought, water deeply but infrequently.

Avoid excessive fertilizer. Snow-in-Summer performs well in moderately poor soil, and heavily enriched conditions may encourage foliage growth at the expense of compact flowering.

The plant spreads through creeping stems and may also self-seed. Monitor its edges and remove unwanted growth to keep it within the intended planting area.

Snow-in-Summer is not suitable for frequently walked-on surfaces, as repeated foot traffic can damage the foliage.

STEP 5 — ENCOURAGE FLOWERING AND HEALTHY REGROWTH

Established plants produce masses of small, white, star-shaped flowers during late spring and early summer.

Seed-grown plants may flower during their first year under favorable conditions, although a fuller display is more likely after the groundcover has become established.

AFTER FLOWERING:

Trim away spent flowering stems and lightly shear the foliage to encourage compact, fresh growth.

Avoid cutting deeply into unhealthy or bare sections that show little active growth.

Removing spent flowers before seeds mature can also help limit unwanted self-seeding.

Every few years, established clumps can be divided in spring or early fall to rejuvenate crowded patches or fill gaps in the planting area.

WINTER CARE AND LONG-TERM GROWTH

Snow-in-Summer is a hardy perennial that may retain some foliage through winter, depending on local temperatures.

In colder climates, foliage may become flattened or discolored before fresh growth resumes in spring.

Avoid heavy winter watering and ensure the planting area remains well drained.

Established mats may develop sparse or bare centers as they age. Remove dead material and replant healthy divisions where necessary.

Because Snow-in-Summer can spread aggressively under favorable conditions, monitor its growth near neighboring plants and natural areas.

IMPORTANT GROWING CONSIDERATIONS

Snow-in-Summer is native to parts of Europe and is not a native North American groundcover.

It may spread beyond its intended planting area in some regions. Check local planting recommendations and avoid introducing it into nearby natural habitats.

Although hardy in cold winters, it may perform poorly in regions with persistently hot, humid summers or heavy, poorly drained soil.