Yellow Nutsedge

Yellow Nutsedge (Cyperus esculentus)

Report

Photo credit: John W. Everest, Auburn University, Bugwood.org

Management Strategy

Synonyms

Yellow nut-grass
Chufa
Earth almond
Edible nutgrass
Northern nutgrass
Rush nut
Tiger nut

ID Characteristics

Perennial herb from the Cyperaceae (Sedge) family. Cyperus esculentus means ‘abundant edible sedge’, likely due to its mild almond taste. Ancient wall paintings from Egypt indicate that this plant was cultivated as early as 400 BC. Even pigs are reported to be very fond of its starchy tubers!

Flowers: Inconspicuous (small, hard to see) flowers arranged into numerous narrow, straw-coloured clusters within a branched, umbrella-shaped flowerhead at the end of the stem.

Stems: Are unbranched, smooth, and under 1 m tall (0.1 – 0.9 m), with a triangular cross-section.

Leaves: Yellow to green elongated leaves (3 – 8 mm wide) with a distinct mid-vein and a pointed tip. Leaves are typically clustered at the base of the plant.

Roots: Underground structures include fibrous roots, rhizomes, tubers and bulbs. Notably, tubers are white, smooth and almond-flavoured.

Fruits: Are oval and yellowish-brown and contain one seed.

Similar Species

Invasive:

Purple Nutsedge, Credit: C. Bryson, USDA Agricultural Research Service, Bugwood.org

Purple nutsedge (Cyperus rotundus) can be distinguished by its darker leaves and red-brown to purple flower clusters. Tubers are dark, taste very unpleasant, and are attached to a wiry rhizome.

Habitat and Origin

Yellow nutsedge was introduced from Europe. Since 1950, it has been considered one of the world’s worst weeds, as it is currently found on all continents except Antarctica.

Yellow nutsedge is highly adaptable: it grows in well-drained and sandy soils, but also in very wet soils. It typically occurs in riparian areas, wet fields, irrigated crop fields, roadsides and ditches. It is considered a pioneer species and can colonize recently disturbed areas.

How it Spreads

Yellow nutsedge spreads vegetatively (by rhizomes and tubers), and occasionally by seed. Tubers can remain viable in the soil for up to 4 years and can regenerate new plants. One tuber can give rise to hundreds of shoots, which, in turn, can go on to create thousands of new tubers.

Local dispersal occurs primarily through rhizomes, tubers and bulb growth. However, long-distance dispersal occurs when seeds are transported by wind, agricultural and nursery activities, soil movement, and water.

Impacts

Ecological:

Outcompetes native vegetation, forming dense monocultures.
Can transmit pests and diseases.

Economic:

Decreases amenity values.
Can impact tourism.
Reduces resource availability for crops, reducing crop yields.

Stop the Spread

Yellow nutsedge is not yet found in the Sea to Sky region, but is found in neighbouring areas and may arrive here soon. The goal is to prevent yellow nutsedge’s introduction by focusing on education and awareness. If prevention fails, the goal will become immediate eradication following the proposed SSISC EDRR protocol.

Learn to identify yellow nutsedge: use the images presented on this profile page to learn how to identify yellow nutsedge.

What to do if you spot it: You can report any yellow nutsedge sighting by visiting our reporting page.

DO:

Regularly monitor properties for weed infestations.
Minimize soil disturbances and promptly revegetate disturbed areas to prevent the growth of yellow nutsedge.
Check wildflower mixes to ensure that they do not contain yellow nutsedge.
Ensure all flowering heads or buds are bagged or covered to prevent spread during transport to designated disposal sites.

DO NOT:

Unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
Plant yellow nutsedge in a garden, no matter how well-contained its enclosure may seem.
Compost any flowering heads or buds. Instead, dispose of yellow nutsedge in the general/household waste stream at the landfill as the seeds will be able to persist the composting process.
Move soil, gravel, or fill that has been contaminated with yellow nutsedge.

Control

Mechanical

Prevent plants from developing tubers by removing young plants as soon as possible.
If plants have already formed tubers, dig 20 – 30 cm into the soil to remove roots.
Removal may prove challenging due to its layered root system.

Chemical

Glyphosate has proven effective on yellow nutsedge infestations.
We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Biological