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Arenaria spp.
sandwort
Northern Hemisphere (Europe, Asia, North America)
Attracts PollinatorsAttracts ButterfliesDeer ResistantDrought TolerantContainer Friendly
Native to North America
Overview
Arenaria spp. is a large genus of small, mostly perennial herbs in the pink family Caryophyllaceae, known as sandworts, with well over 100 species spread across the temperate and cold regions of the Northern Hemisphere and the mountains farther south. Most form low cushions, tufts, or creeping mats 1-8 inches (2.5-20 cm) tall, with wiry stems and small, narrow leaves 0.1-0.6 inch (3-15 mm) long that are often crowded and stiff. In late spring and summer the plants carry many small, five-petaled white flowers 0.2-0.5 inch (5-12 mm) across, the petals usually notched at the tip and held above the foliage on slender stalks. A few species are annuals of bare, sandy ground, but the cushion- and mat-forming perennials are the most familiar, including A. montana, grown for its comparatively large white flowers. The genus grows on rocky slopes, scree, sandy soil, gravelly ground, and alpine turf, almost always in open, well-drained, sunny sites. Plants tolerate cold, wind, and poor soil but rot in heavy, wet, or shaded conditions. The dense, evergreen cushions of many species hold their shape year-round and slowly spread to fill gaps between rocks.
Native Range
Native across the temperate and cold parts of the Northern Hemisphere, with many species in the mountain ranges of Europe, Asia, and North America. Plants grow on rocky slopes, scree, sandy ground, and alpine turf in open, well-drained sites.Suggested Uses
Arenaria spp. is grown in rock gardens, troughs, gravel gardens, scree beds, and the gaps between paving, where its low cushions suit alpine and dry plantings. The white flowers draw small pollinators in late spring. Mat-forming species are also grown as a low groundcover for hot, well-drained sites.How to Identify
Appearance
Size & Dimensions
Height1" - 8"
Width/Spread6" - 1'6"
Bloom Information
Flowering occurs mainly in late spring and summer, with the timing later at high elevations. The small white flowers open over several weeks, covering the cushions and drawing small bees and flies. Dry capsules follow, splitting at the tip to shed tiny seed.
Detailed Descriptions
Foliage Description
green to grey-greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Plants grow in full sun in gritty, sharply drained, sandy or rocky soil of low fertility, at a pH near 6.0 to 7.5. The genus needs sharp drainage and dry, airy conditions, rotting quickly in heavy, wet, or shaded ground. Most cushion-forming species are hardy in USDA zones 4 to 8, withstanding cold and wind in their native mountains. Propagation is by seed, by division of mats, or from small cuttings of non-flowering shoots. Little feeding is needed, and rich soil or excess water produces soft, short-lived growth. A topdressing of grit around the cushions keeps the foliage dry and discourages rot.Pruning
A light shearing after flowering removes spent blooms and keeps the cushions tight and compact. Dead or rotted patches are cut out and the gaps top-dressed with grit so neighboring growth fills in. No other pruning is needed.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons