Common Name: snow-in-summer
Type: Herbaceous perennial
Zone: 3 to 7
Height: 0.50 to 1.00 feet
Spread: 0.75 to 1.00 feet
Bloom Time: June
Bloom Description: White
Sun: Full sun
Suggested Use: Ground Cover, Naturalize
Tolerate: Deer, Drought, Dry Soil, Shallow-Rocky Soil
Best grown in dry, sandy, well-drained soils in full sun. Tolerates a somewhat wide range of soils except poorly-drained ones which inevitably lead to root rot. Intolerant of the high summer heat and humidity of the deep South. Spreads by runners to fill in areas, but is not too aggressive in the hot St. Louis climate where it is not as robust as in cooler northern climates. Best to shear off flower stems after bloom or mow on high setting to shape foliage mat and hopefully reduce foliage decline. Will self-seed in the garden if spent blooms are not removed. Starter plants may be planted 9-12" apart to quickly cover large areas.
Snow-in-summer is a short-lived, low-growing, mat-forming perennial which is typically massed in sunny locations as a ground cover. Tufts of narrow, silver-gray leaves form a 6" tall foliage mat. In late spring, flower stems rise above the foliage mat (typically to 8-12") carrying clusters (cymes) of white blooms which form a snow-like carpet (hence the common name). Flowers (to 1" diameter) have 5 notched petals and are similar in appearance and closely related (same genus) to several of the chickweeds. Less aggressive, more compact cultivars of this species usually make better garden plants (See, e.g., Cerastium tomentosum 'Yo Yo').
No serious insect or disease problems. Root rot can be a serious problem if plants are grown in poorly-drained soils or in soils that remain wet. Plants are short-lived, and dead patches often begin to appear after several years. In St. Louis, foliage usually declines as the summer progresses.
Ground cover for sunny areas. Rock gardens, border fronts, edgings, bulb cover or dry stone wall planting pockets.