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How to Manage Pests

Identification: Weed Photo Gallery

River bulrush

Scientific name: Scirpus fluviatilis (Sedge Family: Cyperaceae)

Click on image to enlarge

Life stages of River bulrush rhizomes mature plants flower head sprouting tuber

River bulrush, a perennial sedge, is native to most western states. It is not considered a weed in natural settings, but can be problematic. Infestations are localized. It can be troublesome in rice fields that are not rotated with other crops. It also inhabits drainage and irrigation canals. In California, river bulrush is found in the Sacramento Valley, San Francisco Bay region, North Coast Ranges, northern Sierra Nevada, and Modoc Plateau, up to an elevation of about 4300 feet (1300 m).

Seedling

River bulrush seedlings are grasslike and inconspicuous.

Mature plant

The mature plant is found in clumps and patches. It is generally 3 to 5 feet (90–150 cm) tall and has the characteristic triangular stem of the sedge family.

Flower

Leafless stems end in egg-shaped flower clusters below which three to five leaflike structures (bracts) extend, distinguishing it from ricefield bulrush, Scirpus mucronatus, which has only one bract.

Reproduction

River bulrush reproduces from dark brown swellings (tubers) that form on underground stem tips. The tubers are very hard at maturity and difficult to cut with a pocketknife.

Related species/Similar looking plants

Smallflower umbrella sedge
Ricefield bulrush

More information


Statewide IPM Program, Agriculture and Natural Resources, University of California
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