Ricefield Bulrush

Schoenoplectus mucronatus

WA A Cyperaceae
Data Maturity Baseline

Washington State Classification

Class A — Eradication Required Statewide

It is a problematic weed in 43 countries, especially in rice fields.

Quick Reference

Type
aquatic emergent
Origin
Africa, Asia and Europe

Identification

Growth Habit

Ricefield bulrush is a wetland, perennial bulrush species. It has triangular stems that reach a height around 2 to 3 feet at maturity.

Leaves

There are 1 to 2 leaves per culm (stem) that are reduced to a few bladeless sheaths. Ligules are absent.

Flowers

Inflorescences head-like with 4 to 20 spikelets (clusters of flowers), rust colored to straw colored with a greenish center. Uppermost bract under inflorescence spreading to reflexed, 0.4 inches to 3.9 inches long.

Fruit & Seeds

Fruits develop summer through fall. They are dorso-laterally compressed and blackish brown when ripe.

Impact

It is a problematic weed in 43 countries, especially in rice fields. It has documented resistance to herbicides making it difficult to control. Since it is currently only known in one area of Washington, eradication in this State is entirely possible.

Ecology & Spread

Habitat

Ricefield bulrush can be found in rice fields as well as emergent zones and wet soils of ponds and ditches. Please click here to see a county level distribution map of ricefield bulrush in Washington.

Spread Mechanisms

seed vegetative fragments

Reproduction

It reproduces through seed, rhizomes and stolons.

Regional Notes — Puget Sound

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Control Methods

Mechanical

  • Hand pulling is a possible control method, although it is very labor intensive.