Snow-in-summer
Cerastium tomentosum · Caryophyllaceae
A silver-white mat hidden under a snowfall of white flowers in late spring. It runs fast in dry, poor soil and sulks in heat and humidity.
- Size
- 8 in tall, 24 in wide
- Zones
- 3 to 7
- Light
- Full sun
- Flowers
- Late May to late June
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around snow-in-summer
The planner designed this bed around snow-in-summer when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 715 that suit those conditions and its dry soil, and says below why snow-in-summer stands where it does.
The plants
- 1 Snow-in-summer × 8, white
- 2 Cranesbill 'Ballerina' × 8, pink
- 3 Stiff goldenrod × 3, yellow
- 4 Little bluestem 'The Blues' × 5, tan
- 5 Silver sage × 1, silver leaves
- 6 Coneflower 'Green Jewel' × 3, green
- 7 Star of Persia × 3, purple
- 8 Spring starflower × 12, blue
Why this plant
- The only dense clusters. The others are open bowls, flat plates, spires and others. Shape reads at a distance, where colours blur.
- The only white. White sits between stronger colours and calms them.
Why here
- Under the taller plants. It runs back between them as living mulch: there its job is to cover the soil, not to be looked at.
- 8 plants in 2 groups (5 and 3). Seen again further along, the same plant ties the bed together.
- Fine leaf against bold. Stiff goldenrod is beside it: the strongest contrast of leaf there is.
Why now
- In flower for five weeks. From late May to late June.
- In company. With cranesbill 'Ballerina' and star of Persia in late May: 3 kinds at once.
- The only leaves in winter. From November to March it is what there is to look at.
Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. Cranesbill 'Ballerina' flowers longest, for 16 weeks. Stiff goldenrod and little bluestem 'The Blues' anchor the back corners of the bed: the tallest plants on the plan stand there.
The planner's own design check: 10 Excellent, 7 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where snow-in-summer goes in a border
At 8 in it belongs at the front of a bed. In the planner's ten height classes it is low (6 to 12 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
Silver all year and white in flower, so it reads as the lightest thing in the bed. It is too vigorous for a small rock garden, but excellent for covering a dry slope.
- Carpeting dry banks and walls
- Silver groundcover in cool climates
- Edging for hot, dry paths
What to plant with snow-in-summer
Plants recorded as good partners for it, and what each pairing does:
- Sedum 'Dragon's Blood': takes over when it finishes, flowering from late June; low enough (4 in) to stand in front of it; happy in the same dry soil.
- Creeping thyme: in flower together for three weeks, from early June; low enough (3 in) to stand in front of it; happy in the same dry soil.
- Blue fescue: its blue-green leaves are a setting for the flowers, before and after; happy in the same dry soil.
Questions about snow-in-summer
Does snow-in-summer need sun or shade?
Snow-in-summer grows in full sun (6 or more hours of direct sun a day).
It wants dry, sharply drained soil, on the lean side, with no feeding, and little watering once settled. Once settled in, it stands drought.
What zones does snow-in-summer grow in?
USDA zones 3 to 7. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 7 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does snow-in-summer flower in my zone?
In zone 5 it flowers late May to late June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Early June to late June |
|---|---|
| Zone 4 | Late May to late June |
| Zone 5 | Late May to late June |
| Zone 6 | Mid May to late June |
| Zone 7 | Early May to mid June |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should snow-in-summer be planted?
18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.
It grows 8 in (20 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many snow-in-summer plants do I need?
At 18 in apart, set out in staggered rows:
- 5 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 17 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as threes and fives, along the front and just behind it.
In the bed above, the planner used eight in two groups.
Is snow-in-summer poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like snow-in-summer?
Snow-in-summer comes from Italy, Corse & Sicilia. These North American natives come closest to doing its job:
- Mountain avens: the same job in a bed, the same flowering time and the same colour; 5 in shorter, wants average soil.
- Three-toothed cinquefoil: the same job in a bed, the same flowering time and the same colour; 6 in narrower.
- Heath aster 'Snow Flurry': the same job in a bed, the same size and the same colour; flowers mid September to mid October, not evergreen.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat snow-in-summer?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will snow-in-summer spread?
It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads steadily by creeping stems. It is easy to pull out, but needs a firm edge.
What flowers after snow-in-summer?
Snow-in-summer is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Sedum 'Dragon's Blood': from late June to early August, 4 in tall, to stand in front of it and cover its fading stems (a recorded partner).
- Black-eyed Susan: from mid July to mid September, 24 in tall.
- Butterfly weed: from late June to early August, 24 in tall.
What does snow-in-summer look like in winter?
Snow-in-summer keeps its silver leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
Is snow-in-summer good for bees and butterflies?
Snow-in-summer is visited by bees.
In these guides
- Deer-resistant perennials for full sun
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Plants for bees
- Low plants for the front of a border
- Groundcover plants
- Evergreen perennials, ferns and grasses
- Plants for a white garden
- Silver and grey-leaved plants
Every fact on record
- Type
- Perennial (groundcover)
- Size
- 8 in (20 cm) tall, 24 in (60 cm) wide
- Plant
- 18 in (45 cm) apart
- Height class
- Low (6 to 12 in)
- Place in the bed
- Front
- Flowers
- Late May to late June; dense clusters; white
- Leaves
- Fine texture, evergreen; silver
- Shape
- Mat-forming, spreading
- Hardy in
- USDA zones 3 to 7
- Light
- Full sun
- Soil
- Lean, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Caryophyllaceae
- Comes from
- Italy, Corse & Sicilia
- Attracts
- Bees
- Stands up to
- Deer, drought, poor soil
Checked against NC State Extension and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.