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Giant Spikerush Eleocharis interstincta

Other Common Name(s):

Previously known as:

  • Scirpus interstinctus
Description

Giant spikerush is a perennial grasslike rush in the Cyperaceae (sedge) family that grows in the margins of ponds and lakes.  It has an upright habit with stems that emerge from thick rhizomes and can reach 4 feet tall. It has no leaves, but it does have long sheaths at the stem base that are often tinged dark-red. The inflorescence is a single, long, cylindrical spikelet at the tip of the stem that is covered with brown, broadly rounded scales. The spikelet has up to 140 small flowers that mature into small, shiny nutlets. The flowers may not be considered showy, however, they are interesting.  The stem is segmented with light green lines showing the segment walls.

Spreading by rhizomes, large patches of giant spikerush can be formed.

This plant grows in freshwater wetlands in full sun and is found in TX, GA and FL in this country but also in Mexico and South America. 

Ducks, geese, and muskrats all eat portions of this plant.  Submerged portions of the plant provide protection to a variety of fish and other water wildlife.

Insects, Diseases, and Other Plant Problems: No significant problems

Salt water and spray can cause the leaves to burn.  

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#water garden#rain garden#wetlands#fish#pond garden#lakes#grass-like#marshes#naturalized area#wet soils tolerant#waterfowl#rushes#drought intolerant#salt spray intolerant#salt intolerant#grass#freshwater habitat
 
Cultivars / Varieties:
Tags:
#water garden#rain garden#wetlands#fish#pond garden#lakes#grass-like#marshes#naturalized area#wet soils tolerant#waterfowl#rushes#drought intolerant#salt spray intolerant#salt intolerant#grass#freshwater habitat
  • Attributes:
    Genus:
    Eleocharis
    Species:
    interstincta
    Family:
    Cyperaceae
    Uses (Ethnobotany):
    Often used for natural setting landscape and the restoration of habitats.
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Seed
    Country Or Region Of Origin:
    Tropical and subtropical Americas
    Distribution:
    Alabama, Texas, Georgia and Florida
    Wildlife Value:
    The plant is eaten by pond wildlife and provides habitat for waterfowl and fish.
    Play Value:
    Wildlife Cover/Habitat
    Wildlife Food Source
    Dimensions:
    Height: 1 ft. 0 in. - 4 ft. 0 in.
    Width: 1 ft. 0 in. - 3 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Ornamental Grasses and Sedges
    Habit/Form:
    Clumping
    Erect
    Growth Rate:
    Medium
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    High Organic Matter
    Soil Drainage:
    Frequent Standing Water
    Occasional Flooding
    Available Space To Plant:
    12 inches-3 feet
    USDA Plant Hardiness Zone:
    9a, 9b, 10a, 10b, 11a, 11b
  • Fruit:
    Fruit Color:
    Brown/Copper
    Gold/Yellow
    Gray/Silver
    Fruit Type:
    Achene
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    The small nutlets are smooth and shiny and bulge on both sides. The nutlets that each contains 1 seed do not open when ripe.
  • Flowers:
    Flower Color:
    Brown/Copper
    Flower Inflorescence:
    Spike
    Flower Value To Gardener:
    Showy
    Flower Bloom Time:
    Spring
    Summer
    Flower Size:
    < 1 inch
    Flower Description:
    Singular spiklet, with 50 to 140 small flowers, and rounded brown scales and stiff short hairs, cylindrical and found at the tip of the stems.
  • Leaves:
    Leaf Color:
    Green
    Red/Burgundy
    Leaf Type:
    Sheath
    Hairs Present:
    No
    Leaf Description:
    No leaves but has sheathes with a dark reddish color at the base
  • Stem:
    Stem Color:
    Green
    Red/Burgundy
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Round
    Stem Form:
    Straight
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    1/2" diameter segmented hollow, green stems with light green lines up to 4 feet tall.
  • Landscape:
    Landscape Location:
    Pond
    Riparian
    Landscape Theme:
    Native Garden
    Rain Garden
    Water Garden
    Attracts:
    Frogs
    Small Mammals
    Resistance To Challenges:
    Wet Soil