Petrosedum spp.
stonecrops
Overview
Petrosedum is a genus of evergreen, mat-forming succulent perennials and subshrubs in the family Crassulaceae, segregated from Sedum and native to Europe, the Mediterranean region, and western Asia. Plants form low spreading carpets 4 to 12 inches (10 to 30 cm) tall, with trailing or ascending stems clothed in narrow, cylindrical, blue-green to gray-green leaves that crowd toward the stem tips. The fleshy leaves store water, allowing the plants to grow in thin, dry soils. In summer, branched flower stems rise above the foliage and unfurl from a coiled, nodding bud to carry flat clusters of small star-shaped flowers, usually bright yellow. The genus grows on rocky outcrops, cliffs, walls, and stony slopes across its range, rooting in shallow pockets of gritty soil. Plants tolerate drought, heat, and poor soil and spread by creeping stems that root where they touch the ground. A limitation is intolerance of wet, heavy soils and shade, under which the stems stretch, rot, or fail to flower. Several species and forms are grown as drought-tolerant groundcover and in green-roof plantings.
Native Range
Petrosedum is native to Europe, the Mediterranean basin, and western Asia. Species grow on rocky outcrops, cliffs, old walls, and stony slopes, often on limestone or other free-draining substrates.Suggested Uses
Petrosedum species are used as drought-tolerant groundcover, in rock gardens, troughs, and wall crevices, and in extensive green-roof plantings. The mat-forming, evergreen habit suits hot, dry, sharply drained sites where little else grows.How to Identify
Appearance
Size & Dimensions
Height4" - 1'
Width/Spread1' - 2'
Colors
Bloom Information
Petrosedum flowers in summer, roughly June through August. The flower stalks rise from coiled buds and open into flat clusters of yellow flowers held above the foliage. After seed sets, the spent flower stems are left standing or removed, while the evergreen foliage persists year-round.
Detailed Descriptions
Foliage Description
blue-green to gray-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
Across the genus, Petrosedum grows in full sun and sharply drained, gritty or sandy soil of low fertility, with a soil pH of about 6.0 to 7.5. Established plants tolerate drought, heat, and poor soil and are watered sparingly, as wet ground causes stem and root rot. The creeping stems root readily, and new plants are started from stem cuttings or divisions laid on gritty soil. In shade the stems stretch and flower poorly. Plants are grown in rock gardens, troughs, wall crevices, and green roofs where drainage is sharp. Little or no fertilizer is needed.Pruning
Spent flower stems can be sheared off after bloom to tidy the mat. Stems that grow leggy or die out in the center are cut back, and the trimmings can be rooted as cuttings to fill gaps. Plants tolerate shearing during the growing season to keep the carpet dense.Container Growing
Suitable for container growing
Minimum container size: 1 gallons