Java Grass Cyperus rotundus
Other Common Name(s):
- Phonetic Spelling
- sy-PEER-us ro-TUN-dus
- Description
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Cyperus rotundus, or Purple Nutsedge, is a perennial, glossy-green, grass-like Eurasian sedge or weed with an erect triangular stem branching into three stems of purple, antenna-like seedpods. Plants die back to the ground in fall, with new shoots emerging in spring from underground tubers. This species, as well as other sedges, grows best in wet sites, prefers warm weather and full sun conditions, but will grow in a diversity of sites and environments.
Like its native cousin, Yellow Nutsedge (Cyperus esculentus), Purple Nutsedge spreads through slender elongated rhizomes and tubers found at the base of the stem and is destructive to crops in sunny, open fields and dry, disturbed soil. The rhizomes remove nutrients from the soil robbing their fellow plants and can be very difficult to remove. If you pull it up you can see the nut-like nodules that store the nutrients (and are edible) as well as a network of long roots. Unfortunately, once pulled up, the Nutsedge may leave broken roots to form more numerous roots and therefore, new plants in its place and seeds lay dormant for several years. It is best to remove young plants and leave exposed roots in the sun to dry out. It is considered one of the world’s worst weeds and is reported in more than 90 countries as a weed infesting at least 52 different crops.
Diseases, Insects, and Other Plant Problems:
No known insect or disease problems. This plant is allelopathic and removes nutrients from soil and its existence in a field significantly reduces crop yield. It is resistant to most herbicides and is one of the few weeds that cannot be stopped with plastic mulch.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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Attributes:
- Genus:
- Cyperus
- Species:
- rotundus
- Family:
- Cyperaceae
- Uses (Ethnobotany):
- Roots are staple carbohydrate in topical regions. Also used homeopathically.
- Life Cycle:
- Perennial
- Recommended Propagation Strategy:
- Division
- Root Cutting
- Seed
- Country Or Region Of Origin:
- Tropical and Subtropical Old World
- Distribution:
- Southern and South Central United States
- Particularly Resistant To (Insects/Diseases/Other Problems):
- drought
- Edibility:
- Tuber can be eaten but is described as more bitter and less useful than its near cousin, Cyperus esculentus.
- Dimensions:
- Height: 2 ft. 0 in. - 4 ft. 7 in.
- Width: 0 ft. 2 in. - 0 ft. 5 in.
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Whole Plant Traits:
- Plant Type:
- Herbaceous Perennial
- Weed
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Ascending
- Erect
- Mounding
- Growth Rate:
- Rapid
- Maintenance:
- High
- Texture:
- Coarse
- Appendage:
- Thorns
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Soil Texture:
- Clay
- Loam (Silt)
- Sand
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Moist
- Occasional Flooding
- Occasionally Dry
- Available Space To Plant:
- Less than 12 inches
- NC Region:
- Coastal
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
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Fruit:
- Fruit Color:
- Brown/Copper
- Gray/Silver
- Display/Harvest Time:
- Fall
- Summer
- Fruit Type:
- Achene
- Fruit Description:
- Tiny, triangled smooth achenes.
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Flowers:
- Flower Color:
- Brown/Copper
- Flower Inflorescence:
- Spike
- Umbel
- Flower Bloom Time:
- Spring
- Summer
- Flower Petals:
- Bracts
- Flower Size:
- < 1 inch
- Flower Description:
- Large spikelets in short spikes occur at the ends of the solitary stems in a dense cluster where the flower stalks rise from a common point (umbel-like). Individual spikelets are reddish-purple to reddish-brown in color. Linear-lanceolate and slightly flattened, 1/4 to 3/4 of an inch long, 1/10 of an inch wide. Unequal rays support spikelets.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Brown/Copper
- Gold/Yellow
- Green
- Leaf Feel:
- Glossy
- Smooth
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Hairs Present:
- No
- Leaf Length:
- > 6 inches
- Leaf Width:
- < 1 inch
- Leaf Description:
- Three subtending leaves broad at base tapering to a point. Leaves up to 15 inches long and 1/3 of an inch wide. Scabrid on margin and major veins. Leaf sheath green to reddish-brown. Foliage dies back at first frost
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Stem:
- Stem Color:
- Green
- Stem Is Aromatic:
- No
- Stem Buds:
- Smooth/Hairless
- Stem Bud Terminal:
- Cluster of terminal buds
- Stem Cross Section:
- Angular
- Stem Form:
- Straight
- Stem Lenticels:
- Not Conspicuous
- Pith (Split Longitudinally):
- Spongy
- Stem Surface:
- Smooth (glabrous)
- Stem Description:
- Erect triangular stem on a mat-forming mound. Stems rise from tuber or basal bulb. Rounded, fiber-covered tubers at the stem bases.
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Landscape:
- Resistance To Challenges:
- Drought
- Dry Soil
- Poor Soil
- Wet Soil
- Problems:
- Weedy