Sparganium erectum
branched bur-reed
Europe, temperate Asia, and North Africa
Overview
Sparganium erectum is an emergent perennial of still and slow-moving water in the bulrush family, spreading by stout rhizomes to form dense, erect stands 20-60 inches (50-150 cm) tall. The leaves are long, stiff, and sharply three-angled in cross-section near the base, rising directly from the waterline like those of an iris. From June to August it produces a branched flowering stem bearing separate male and female heads: the smaller male heads cluster toward the tips, while the larger spherical female heads sit lower down. After pollination the female heads ripen into spiky, bur-like balls about 0.8-1 inch (20-25 mm) across, each segment a beaked, corky fruit that floats and disperses on water. The plant roots in mud at the edges of ponds, lakes, ditches, canals, and sluggish rivers, in water up to about 12 inches (30 cm) deep. Its rhizomes spread vigorously and can choke small channels and pond margins. It dies back to the rhizome in winter and resprouts in spring.
Native Range
Native across Europe, temperate Asia, and North Africa, with related forms extending more widely. Common throughout Britain and Ireland at the margins of fresh water.Suggested Uses
Planted at pond, lake, and ditch margins, in wildlife ponds, and in wetland and water-treatment schemes. The dense stands shelter waterfowl, insects, and amphibians, and the seeds feed birds. Its spreading habit suits large, naturalistic water margins rather than small formal pools.How to Identify
Appearance
Size & Dimensions
Height1'8" - 5'
Width/Spread2' - 4'
Bloom Information
Flower heads appear from June to August on the branched stems, the males above the females on each branch. The plant is wind-pollinated and bears no showy petals, releasing pollen onto the lower female heads. Spiky fruiting heads form through late summer and ripen into floating burs.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 5-10 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
Sparganium erectum grows in full sun to light shade in permanently wet mud or shallow standing water up to about 12 inches (30 cm) deep. It needs constant water at the roots and fertile, silty ground, and dies back if the margin dries out for long. Plants are increased by dividing the rhizome in spring or by seed sown into wet mud. Once established the rhizomes spread strongly, so in ponds it is often confined to a planting basket to limit it. Stands are cut back in autumn or winter as the foliage dies down. Deep shade and fast, scouring current reduce it.Pruning
Dying foliage is cut back in late autumn or winter once growth has stopped. Spreading rhizomes are divided or reduced in spring to keep stands within bounds. Old fruiting stems are removed or left as winter structure.Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons