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Eleocharis palustris
Common Spikerush
Cosmopolitan: temperate and boreal North America, Europe, Asia, parts of South America
Overview
Eleocharis palustris is a perennial herbaceous wetland spike-rush forming colonies of upright unbranched stems 6-36 inches (15-90 cm) tall via creeping rhizomes. Plants lack true leaves; the round to slightly compressed stems 0.04-0.12 inch (1-3 mm) thick are photosynthetic. Each stem terminates in a single elongated spikelet 0.3-1 inch (8-25 mm) long with overlapping brown to red-brown scales. Bloom occurs from May through September. Achenes are 0.04-0.06 inch (1-1.5 mm) long, lens-shaped, brown, with a small persistent style base. Rhizomes spread 6-12 inches (15-30 cm) per growing season; established plantings form dense low colonies 5-10 feet (1.5-3 m) wide within 4-5 years. Plants tolerate continuous standing water 4-12 inches (10-30 cm) deep, brackish conditions in coastal areas, and seasonally drying soils. Above-ground tissue persists yellow-brown through winter in zones 7-9 and dies back completely in zones 3-6.
Native Range
Cosmopolitan native, occurring across temperate and boreal North America, Europe, Asia, and parts of South America. Grows in fresh to slightly brackish wetland margins, slow streams, ditches, pond edges, marshes, and seasonally flooded depressions at elevations from sea level to 11,000 feet (3,400 m). Often the dominant emergent species on shallow lake margins.Suggested Uses
Used in pond margins, constructed wetlands, rain gardens, stream-edge erosion control, and shoreline restorations, spaced 12-18 inches (30-45 cm) apart for full coverage in 2-3 years. Plantings combine with Carex aquatilis, Iris versicolor, and Sparganium species in mixed emergent plantings. The rhizomatous habit makes the species incompatible with formal mixed perennial beds.How to Identify
Appearance
Size & Dimensions
Height6" - 3'
Width/Spread5' - 10'
Reaches mature size in approximately 3 years
Bloom Information
Blooms May through September across the range, with peak June through July at mid-latitudes. Individual spikelets mature over 4-6 weeks; new culms emerge throughout the growing season in saturated soils. Achenes shed July through October. Bloom is heavier in continuously flooded sites than in fluctuating-water-level sites.Detailed Descriptions
Flower Description
brown to red-brownFoliage Description
green stems (no true leaves)Growing Conditions
Sun Requirements
Requires 4-9 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
Plantings establish in saturated to seasonally flooded soils with pH 5.5-8.0. Water at planting; established plantings in wet sites require no supplemental water. Tolerates standing water up to 12 inches (30 cm) deep through the growing season. Few pest or disease problems occur. Spreading rhizomes can extend beyond pond margins into adjacent areas; root barriers buried 12 inches (30 cm) deep contain the spread. Old stems are cut to 4 inches (10 cm) above the soil in late winter or left in place to decompose. Fertilization is not required.Pruning
Old stems are cut to 4 inches (10 cm) above the soil in late February or early March before new growth begins, or left to decompose naturally with no impact on plant health. Mid-season grooming is not required. Rhizomes that extend beyond intended planting areas can be cut at the bed edge with a sharp spade in any season.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winterearly spring
Maintenance Level
lowContainer Growing
✓ Suitable for container growing
Minimum container size: 5 gallons