How to Grow Cerastium — Snow-In-Summer

Snow-in-summer Cerastium

Snow-in-summer, Cerastium, is a low-mounding plant with small, wooly leaves and clusters of white flowers on wiry stems. Cerastium grows 6 to 10 inches high and spreads 2 to 3 feet in a year.

Cerastium grows well in most areas except for hot, humid regions where it is best place in shade. Standing water will cause roots to rot.

Use snow-in-summer as an edge to flower borders or ground cover. It can used between stepping stones and in rock gardens. It is a good ground cover for slopes.

White flowers and greyish green foliage of Cerastium tomentosum
White flowers and greyish green foliage of Cerastium tomentosum

Get to Know Cerastium

  • Plant type: Perennial
  • Growing Zones and range: 2-9
  • Hardiness: Hardy to -35°F/-37°C
  • Height and width: 6”- 10” tall (15-25cm); 12” wide
  • Form: Spreading mats of 3/4-inch silver-gray, oval leaves that grow up to 8 inches high
  • Flowers: Masses of small snowy white 5-petaled, deeply notched blossoms
  • Uses: Flowering groundcover, drought tolerant
  • Garden companions: Late spring bulbs, Johnny-jump-ups
  • Bloom time: Late spring or early summer
  • Common name: Snow-In-Summer
  • Botanical name: Cerastium tomentosum
  • Family: Caryophyllaceae

Where to Plant Cerastium

  • Grow Cerastium in full sun.
  • Cerastium will grow in average to poor soil that is well-drained.
Snow-in-Summer, Cerastium tomentosum
Snow-in-Summer, Cerastium tomentosum

When to Plant Cerastium

  • Set Cerastium outdoors in spring in Zones 3-5. Plant in spring or fall in Zones 6-7.

Planting and Spacing Cerastium

  • Space Cerastium 12 to 24 inches (30-61cm) apart.
  • Sow seed 1/8 inch deep in evenly prepared soil.

How to Water and Feed Cerastium

  • Cerastium grows well in dry soil. Moderate water will sustain mature plants.
  • Fertilize Cerastium only occasionally. Too much fertilizer will cause snow-in-summer to grow rapidly and become invasive.

Cerastium Care

  • Divide Cerastium as needed to fill vacant spots in the garden.
  • Cut back foliage after flowering to keep plants neat and full.
  • Cerastium is usually pest and disease free.

Cerastium Common Problems

  • Cerastium can suffer fungal rots that blacken the leaves and stems. Remove and destroy infected plants.

Cerastium Propagation

  • Sow seeds in a cold frame in autumn.
  • Take tip cuttings in early summer.
  • Clumps spread readily; divide clumps in spring or fall.

Cerastium Varieties to Grow

  • ‘Yo Yo’ is less invasive than other cultivars.
  • ‘Silver Carpet’ is a compact selection.

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