Hypericum mutilum
dwarf St. John's wort
Overview
Hypericum mutilum is a slender annual or short-lived perennial herb of the St. John's wort family native to wet meadows, marsh edges, ditches, and shorelines across much of North America. It grows 4-30 inches (10-75 cm) tall on smooth, four-angled, much-branched stems, sometimes rooting at the lower nodes. The opposite, stalkless leaves are oval to lance-shaped, 0.4-1.5 inches (1-4 cm) long, with three to five main veins and a few scattered translucent dots. From midsummer into early autumn it produces many tiny pale yellow flowers 0.1-0.2 inch (3-5 mm) across, each with five petals shorter than or about equal to the sepals, opening in branched, leafy clusters. Small pointed seed capsules follow and split to shed numerous tiny seeds. It needs moist to wet, sunny ground and is short-lived where soils dry out, persisting mainly by abundant self-seeding rather than long-lived crowns. The flowers are small and short-lived, and it is grown chiefly for wetland habitat. In cultivation it is used in rain gardens, pond and bog margins, and wetland restoration.
Native Range
Native across much of North America, from eastern Canada through the United States to Mexico, and naturalized elsewhere. It grows in wet meadows, marshes, swamp and pond margins, ditches, and damp disturbed ground.Suggested Uses
Used in rain gardens, pond and bog margins, wet meadows, and wetland and shoreline restoration. It suits damp, sunny spots where its self-seeding fills moist open ground.How to Identify
Appearance
Size & Dimensions
Height4" - 2'6"
Width/Spread6" - 1'6"
Bloom Information
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-12 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
Grow in full sun to light shade in consistently moist to wet soil; the species tolerates seasonal flooding, mucky ground, and pond edges. It needs reliable moisture and is short-lived or fails where the soil dries out in summer. No fertilizer is needed, and lean wet soils suit it. It self-seeds freely in open damp ground, returning year to year from seed even where individual plants are brief. Spent stems can be cut or left standing; seedlings fill gaps. It is hardy in USDA zones 3-9.Pruning
Little pruning is needed. Spent stems can be cut back in late autumn or left standing through winter for seed dispersal. Shearing lightly after the first flush can prompt a second, smaller bloom.Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons