Snow-in-summer Cerastium tomentosum
Snow-in-summer (Cerastium tomentosum) is an evergreen perennial groundcover in the Caryophyllaceae family, native to Mountains of Italy and Sicily. It grows 10–20 cm (4–8 in) tall and 30–60 cm (12–24 in) wide, wants full sun and low water, and is hardy to about -37 °C (-35 °F). Space plants about 30 cm (12 in) apart.
Plan Snow-in-summer in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Snow-in-summer at a glance
| Type | Perennial groundcover, evergreen |
|---|---|
| Family | Caryophyllaceae |
| Mature height | 10–20 cm (4–8 in) |
| Mature spread | 30–60 cm (12–24 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 6–8 |
| Cold hardiness | About -37 °C (-35 °F) once established (roughly USDA zone 3) |
| Heat stress | Likely above about 28 °C (82 °F) |
| Flowering | from about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Mountains of Italy and Sicily |
| Common in gardens of | 🇩🇪 Germany, 🇬🇧 United Kingdom, 🇺🇸 United States |
Is Snow-in-summer toxic?
- People: not well documented
- Cats: not well documented
- Dogs: not well documented
No toxicity clearly documented in standard references; treat as untested.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Snow-in-summer
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Questions about Snow-in-summer
- How far apart should I plant Snow-in-summer?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).
- Does Snow-in-summer need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Snow-in-summer need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Snow-in-summer?
- It tolerates about -37 °C (-35 °F) once established, roughly USDA zone 3.
- When does Snow-in-summer flower?
- From about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Snow-in-summer poisonous to cats and dogs?
- For cats it is not well documented; for dogs not well documented; for people not well documented. No toxicity clearly documented in standard references; treat as untested.
- What grows well with Snow-in-summer?
- There is no well-documented companion pairing for Snow-in-summer. Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- Extension Gardener Plant Toolbox, NC State Extension
Notes and assumptions
- Fast spreader that can overrun neighbouring plants; declines in hot, humid summers and wet soil.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Sweet William Dianthus barbatus
- Carnation Dianthus caryophyllus
- China pink Dianthus chinensis
- Moss campion Silene acaulis
- Soapwort (bouncing bet) Saponaria officinalis
- Rock soapwort Saponaria ocymoides
- Creeping baby’s breath Gypsophila repens
- Maiden pink Dianthus deltoides