Cerastium Plant Growing & Care Guide for Gardeners

Article by Dean Ravenscroft, Ph.D. - Updated 22nd Nov 2023

In this Gardener's HQ guide, we'll explore cultivating Cerastium plants in your garden, indoor spaces, and other settings.

At a Glance: Cerastium

Plant Characteristics: Cerastium is a mat-forming hardy perennial, known for its small, starry flowers and gray downy leaves. It blooms in early spring or summer, making it a charming addition to gardens with its Chickweed or Snow-in-summer varieties.
Ideal Growing Conditions: This plant excels in full sunlight or light shade, with soil pH between 6.0 and 7.0. It adapts to most soils but thrives best in moist, well-draining soils. For best results, plant in early spring or towards the end of autumn.
General Care: Plants are low-maintenance and drought-tolerant, requiring minimal watering. Appreciates poor soils and does not need regular fertilizing. Pruning after flowering maintains its spectacular appearance.
Tips for New Gardeners: Snow-in-summer is an excellent choice for beginners, offering easy care and adaptability. Key strategies include providing plenty of sunlight, ensuring well-drained soil, and minimal watering.

Chickweed, and Snow in Summer: Cultivation & Garden Use

Cerastium is a mat forming hardy perennial.

It has grey downy leaves. Plants bloom with small starry flowers in either early spring or summer.

It's common names include Chickweed and Snow in summer.

Cerastium tomentosum
Cerastium tomentosum (Snow-in-summer) by Phil Sellen.

Cerastium
Cerastium alpinum (Alpine Chickweed) by Brewbooks.

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Cerastium Growing and Care Guide

Common Names: Chickweed, Snow-in-summer, Mouse eared chickweed, Alpine Chickweed, Common mouse ear.
Life Cycle: Hardy perennial. Winter Annual.
Height: 2 to 18 inches (5 to 45 cm). Mat forming. Tufts.
Native: Temperate regions.
Family: Caryophyllaceae.
Growing Region: Zones 3 to 9.
Flowers: Species dependent: Early spring or/and summer.
Flower Details: Herbaceous. White. Small. Star-shaped.
Foliage: Grey, silver, green. Downy. Elliptical.
Sow Outside: Cover Cerastium seeds. Start of spring - before the last frost, or towards the end of autumn. Spacing 4 to 18 inches (10 to 45 cm).
Sow Inside: Germination time: one to two weeks. Temperature 65 to 75°F (18 to 24°C). Seven or eight weeks in advance. Transplant outdoors following the last frost or in autumn.
Requirements: Full sunlight or light shade. Soil pH 6.0 to 7.0. Most soils, best results in moist ones. Cut back once flowering has completed. Divide after two or three years to maintain vigour. Propagate: by dividing in the spring in cool regions or the autumn in warmer climes. Cuttings can be taken in the early months of summer.
Miscellaneous: Attractive to many species of moths from the Coleophora genus

How to Grow Cerastium

It is best to sow Cerastium seeds outdoors in the early spring before the last frost. Simply cover the seeds with top soil.

They should be planted into an area of the garden that has a moist soil pH of 6 to 7.

Snow in the summer prefers to grow in a partially shaded or a sunny part of the garden.

If you plan to start Cerastium plants indoors first, then they should be started about seven weeks before they are due to put outside. This can be in either autumn or after the last frost of the spring.

They usually take between one and two weeks to germinate at a temperature of 18 to 22 degrees Centigrade (64 to 72°F).

Once Cerastium seedlings are ready, they should be transplanted out at a spacing of 15 cm / 6 inches (small species) to 40 cm / 16 inches (large species).

Looking after Cerastium in the Garden

Snow in summer and other members of Cerastium are easy to look after, simply cut them back after they have flowered. Divide the plant every three years.

If you require more plants, then cuttings of Cerastium can be took in the summer.

Common Questions

How many members does the Cerastium genus have?

The Cerastium genus consists of around 100 species.

Do members of Cerastium make a good garden or landscaping plant?

Yes, Cerastium species like Cerastium tomentosum (Snow-in-Summer) can provide lovely ground cover with silvery foliage and white flowers.

Which Cerastium species are most frequently grown by gardeners?

Cerastium tomentosum (Snow-in-Summer) is a popular choice due to its carpet of white blooms in late spring and early summer.

Are members of the Cerastium plant genus fragrant?

Cerastium plants do not have a significant fragrance.

What is the perfect location to grow Cerastium?

Cerastium thrives in full sun with well-drained soil, making it ideal for rock gardens and as ground cover.

Is Cerastium invasive in the USA?

Cerastium tomentosum (Snow-in-Summer) can become invasive in some areas due to its vigorous growth habits, particularly in the Midwest.

How do I remove Cerastium plants from my garden?

Control Cerastium by digging out the plant, making sure to remove all the roots. Regular mowing before it sets seed can also help.

Summary

The Cerastium genus, also known as mouse-ear chickweed, belongs to the Caryophyllaceae family and is native to various regions around the world. These low-growing perennials are recognized for their dense, silvery foliage and white, star-shaped flowers that bloom in spring and summer.

Cerastium thrive in full sun to partial shade, in well-drained soil. They can be grown from seeds or cuttings, and once established, spread rapidly to form a mat. Regular watering is necessary, but they are quite drought-tolerant. They are often used as ground cover or in rock gardens.

I hope that you found this guide on how to grow Cerastium plants in your garden. You may also enjoy my gardening guides on how to grow Tunic Flower, Lychnis plant, and Gypsophilia plants.

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