Common Name: Nut Grass

General Information

Cyperus rotundus is a perennial grass-like plant producing a clump of leaves usually around 10 - 30cm tall, but sometimes to 75cm[]. The plant spreads rapidly at the roots.
The plant is harvested from the wild for local use, mainly as a medicine but also for food, essential oils and basketry. It is sometimes cultivated for its edible tubers in Tropical regions[].
Cyperus rotundus is widespread with stable populations and does not face any major threats. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2018)[].
Cyperus rotundus is a serious weed of agricultural land, especially in the tropics where it spreads rapidly at the roots[] and is considered to be one of the world's most damaging weeds[, ]. It is subject to statutory control in several countries[].

Known Hazards

None known

Botanical References

, ,

Range

Widespread from the warm temperate to the tropical zones of southern Europe, Africa, Asia, Australia, the Pacific and the Americas.

Habitat

Roadsides, sandy fields and cultivated ground[]. Found in a wide variety of wetland habitats including seasonally wet grasslands, swamps, drainage lines and ditches, pond and lake margins, springs, stream and river banks[].

Properties

Weed Potential	Yes
Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.30 m
Cultivation Status	Cultivated, Wild

Cultivation Details

Widespread from the warm temperate zone to the tropics, where it is found at elevations up to 800 metres. It grows best in areas where annual daytime temperatures are within the range 24 - 32°c, but can tolerate 10 - 45°c[]. It can be killed by temperatures of -5°c or lower[]. It prefers a mean annual rainfall in the range 500 - 3,000mm, but tolerates 300 - 4,200mm[].
Prefers a moist sandy loam[, ] and a sunny position[]. Prefers a pH in the range 5.5 - 7, tolerating 3.5 - 8[].
This plant is sometimes cultivated for its edible tubers in Tropical regions[], however it is a serious weed of agricultural land in the tropics where it spreads rapidly at the roots[61

Edible Uses

Tuber - raw or cooked[, , , , ]. A very strong flavour when freshly harvested, said to resemble 'Vick's VapoRub', the tubers become milder if they are allowed to dry[]. A pleasant nutty flavour according to another report[] whilst another says that the roots are very unpalatable raw and a little better but still not very palatable when cooked[]. The dried roots can be ground into a powder and used as a cereal[].

Seed. A famine food, used when all else fails[]. It is very small and would be fiddly to use[].

We have no specific information for this species, but it is said that the inner base of the young stems of all species in this genus can be eaten raw, and make an excellent survival food in times of need[].

Medicinal

Nut grass is a pungent bitter-sweet herb that relieves spasms and pain, acting mainly on the digestive system and uterus[]. The roots and tubers are analgesic, antibacterial, antispasmodic, antitussive, aromatic, astringent, carminative, diaphoretic, diuretic, emmenagogue, litholytic, sedative, skin, stimulant, stomachic, tonic and vermifuge[, , , , , , , , ].
They are used internally in the treatment of digestive problems and menstrual complaints[]. They are commonly combined with black pepper (Piper nigrum) in the treatment of stomach-aches, gastralgia, dyspepsia, diarrhoea and vomiting.[, ].
The roots are harvested in the summer or winter and are dried for later use[].

An essential oil in the tubers has antibiotic activity and has been shown to arrest the growth of Micrococcus pyrogenes[].

The plant is rated 8th amongst 250 potential antifertility plants in China[].

The plant is used in the treatment of cervical cancer[].

Other Uses

The leaves are used in basketry and for weaving hats, matting etc[].

The aromatic root is used for perfumery in India[, , ]. When dried and ground into a fine powder it is used like talcum powder[]. The tuber is also used as an insect repellent and to scent clothes in the cupboard[].

Propagation

Seed - surface sow in the spring and keep the compost moist[]. The seed usually germinates in 2 - 6 weeks at 18°c[]. Prick out the seedlings into individual pots as soon as they are large enough to handle. Grow on for their first winter in a greenhouse and plant them out in late spring after the last expected frosts.
Division in spring or autumn. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.