Knotted Spikerush Eleocharis interstincta
Other Common Name(s):
Previously known as:
- Scirpus interstinctus
- Phonetic Spelling
- ee-lee-OK-ar-is in-ter-STIK-tah
- Description
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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:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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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.
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Whole Plant Traits:
- Plant Type:
- Ground Cover
- Herbaceous Perennial
- Ornamental Grasses and Sedges
- Habit/Form:
- Clumping
- Erect
- Growth Rate:
- Medium
- Maintenance:
- Low
- Texture:
- Medium
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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
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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.
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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.
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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
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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.
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Landscape:
- Landscape Location:
- Pond
- Riparian
- Landscape Theme:
- Rain Garden
- Water Garden
- Attracts:
- Frogs
- Small Mammals
- Resistance To Challenges:
- Wet Soil
