Quick Facts

Quick facts

• Yellow Nutgrass (Cyperus esculentus) is a sedge found in many places around the world, but probably native to the Mediterranean region and Africa.
• It is often confused with Nutgrass (C. rotundus) and related species.
• It is much less commonly naturalised in Australia than Nutgrass, but is a pest in some Queensland crops.
• Its small tubers (commonly called chufa or tiger nuts) have been eaten as a snack.

What Does It Look Like?

What is it?

Yellow Nutgrass (Cyperus esculentus) is a slender perennial sedge, with slender rhizomes (underground stems) that produce globular to egg-shaped edible tubers (commonly called 'nuts') about 1 cm in diameter and with a yellow-brown, smooth to slightly fibrous coat. Its stems are triangular in cross-section, smooth, but often rough near the top, 10–70 cm high and 1–4 mm in diameter. Its grass-like leaves can be longer or shorter than the stems and are 3-6 mm wide.

The inflorescence (flowering structure) consists of elongated clusters of numerous yellowish brown, flattened flowers on branches to 10 cm long.

Its fruit/seed (a small nut) is about 1.5 mm long and broadly triangular in cross-section, and grey-brown (Wilson 1993, 1994).

For further information and assistance with identification of Yellow Nutgrass contact the herbarium in your state or territory.

Flower colour

Green, Yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Yellow Nutgrass occurs in disturbed habitats such as parks and gardens, occasionally in agricultural situations (Wilson 1993).

Are there similar species?

Yellow Nutgrass is closely related to introduced Nutgrass (Cyperus rotundus) and the native species C. bifax and C. victoriensis. It can be distinguished from all of them by its yellowish to dark golden brown flowers heads (red-brown to dark purplish brown in the other species), the usually hairy branches in its inflorescence (not hairy in the other species), its yellowish brown rhizomes (purplish to dark brown in the other species) and its round to egg-shaped 'nuts' that have a minutely hairy grey covering when mature (more or less oval and fibrous, but not hairy, in the other species). It usually prefers cooler regions than C. rotundus, but they can be found growing together in coastal New South Wales (Blake 1942; Auld & Medd 1992; Wilson 1993; European and Mediterranean Plant Protection Organization 2008; Wilson 2007 pers. comm.).

Why Is It A Weed?

What are its impacts?

Agriculture: Yellow Nutgrass can invade a large number of crops, and is also known to invade natural environments (Tasmanian Department of Primary Industries and Water 2007). In Queensland, Yellow Nutgrass has been reported as a pest of summer crops on the near north coast and in sugar cane on the far north coast (Kleinschmidt & Johnson 1977).

How does it spread?

Yellow Nutgrass produces small tubers that aid vegetative spread in the soil. In the past, the species was sometimes grown for these edible tubers (Kloot 1979). It also produces seeds occasionally (European and Mediterranean Plant Protection Organization 2008; Wilson 2007 pers. comm.).

What is its history in Australia?

Yellow Nutgrass has been in Australia since about the 1880s, when it was imported because of its tasty small tubers, which were eaten roasted as a snack (known as 'chufa' or 'tiger nuts'). Its popularity waned by about 1900, possibly as a result of substitution with the less tasty tubers of Nutgrass (Cyperus rotundus) (Kloot 1979).

How To Manage It?

Best practice management

The control measures used for the more common Nutgrass (Cyperus rotundus) are likely to be effective on Yellow Nutgrass. These include use of a combimation of chemical spraying and cultivation practices which can assist in control over time (Kleinschmidt & Johnson 1977).

Non-chemical control: Physical control: Nutgrass is difficult to eradicate because of its extensive system of underground rhizomes and tubers (Kleinschmidt & Johnson 1977). Repeated deep cultivation is effective, but if not sustained, can actually stimulate growth (Parsons & Cuthbertson 2001). Because spread is almost totally by human activity, strict hygiene and preventive measures are very effective in containing infestations, although some chemical control is possible (European and Mediterranean Plant Protection Organization 2008).

Chemical control: Is difficult and, used alone, selective herbicides are not effective enough. There has also been a long history of unsuccessful attempts at biological control (Parsons & Cuthbertson 2001).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Yellow Nutgrass flowers in spring to summer (Wilson 1993, 1994). The tubers may become dormant for a period of several seasons, usually sprouting and spread in the spring in Europe (Holm et al. 1977; Stoller & Sweet 1987; European and Mediterranean Plant Protection Organization 2008).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, VIC

What areas within states and territories is it found?

Yellow Nutgrass is only naturalised sporadically, mostly in coastal areas of eastern Australia (New South Wales, Queensland and Victoria) (Wilson 1993). Yellow nut sedge is not known to be present in Tasmania, although plants thought to be yellow nut sedge, now apparently eradicated, were detected in the state's northeast in 1995 (Tasmanian Department of Primary Industries and Water 2007).

Where does it originate?

Yellow Nutgrass is cosmopolitan and is a serious weed of subtropical and temperate cultivation in other parts of the world. It is hard to be sure now, but it is probably native to southern Europe and northern Africa (Bendixen & Nandihalli 1987; Wilson 1993).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, TAS, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Cyperus esculentus

Other scientific names (synonyms)?

Does it have other known common name(s)?

Yellow Nut Sedge, Yellow Nutsedge, Chufa, Earth Almond, Tiger Nut, Northern Nutgrass, Nutgrass, Rush Nut