Hypericum elodes
marsh St John's-wort
Overview
Hypericum elodes is a creeping, mat-forming perennial of acid bogs and shallow water margins, with soft, woolly grey-green stems that root as they trail and turn up at the tips to 4-12 inches (10-30 cm). The rounded to oval leaves, 0.4-0.8 inch (1-2 cm) long, are densely clothed in soft hairs that give the whole plant a grey, felted feel uncommon among St John's-worts. From midsummer to early autumn it bears small clusters of pale yellow five-petaled flowers 0.5-0.6 inch (12-15 mm) across at the stem tips, the petals sometimes red-tinged at the edges and shorter than the surrounding sepals. Small capsules follow and shed tiny seed. The plant grows in wet, peaty, acidic ground at the edges of pools, ditches, and bog gardens, often standing in shallow water, and spreads steadily into low mats. It dies back to creeping overwintering stems in winter. It cannot tolerate lime, drought, or deep shade and is restricted to permanently wet, acidic sites. Its low woolly mat and pale flowers stay close to the ground rather than rising into the border.
Native Range
Hypericum elodes is native to western Europe, from Britain and Ireland south to Portugal and into northwest Africa, growing on wet, acidic, peaty ground. It occupies the margins of pools, bog pools, ditches, and seepages on heaths and moors.Suggested Uses
Grown at the wet, acidic margins of wildlife ponds, in bog gardens, and in peaty containers for its low woolly mats and summer flowers. It suits naturalistic and conservation plantings on acid ground. Its creeping habit knits together the bare wet edges of pools.How to Identify
Appearance
Size & Dimensions
Height4" - 1'
Width/Spread1' - 2'
Bloom Information
Detailed Descriptions
Foliage Description
Grey-green, woollyGrowing Conditions
Sun Requirements
Requires 4-10 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
Grows in full sun to part shade in permanently wet, peaty, acidic soil at the margins of pools, bog gardens, and shallow ditches, often standing in a little water. It is hardy to USDA zone 6 and dies back to creeping overwintering stems in winter. Constant moisture and acidic, lime-free conditions are needed, and the plant fails on dry or chalky ground. It spreads by rooting stems into low mats and may need thinning at the edges. Few pests trouble it, and drought and lime are the main causes of decline.Pruning
No formal pruning is needed. Overlong creeping stems are trimmed back to keep the mat within bounds. Old growth dies down on its own in winter and is cleared as it decays.Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons