Why Is It a Noxious Weed?
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.
How would I identify it?
Ricefield bulrush is a wetland, perennial bulrush species. It has triangular stems that reach a height around 2 to 3 feet at maturity.
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.
There are 1 to 2 leaves per culm (stem) that are reduced to a few bladeless sheaths. Ligules are absent.
Stems (culms) are triangular in cross-section and between 15 and 39 inches tall.
Fruit Seed Description
Fruits develop summer through fall. They are dorso-laterally compressed and blackish brown when ripe.
Where does it grow?
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.
How Does it Reproduce?
It reproduces through seed, rhizomes and stolons.
How Do I Control It?
General Control Strategy
Better land and water management in rice fields can help with control efforts as well as preventing further infestation.
Hand pulling is a possible control method, although it is very labor intensive.
In rice fields, crop rotation that allows the field to completely dry up can help control this weed.
For More Information
See our Written Findings for more information about ricefield bulrush (Schoenoplectus mucronatus).