Nassella tussock

Nassella tussock

Nassella trichotoma

Common Name:

Nassella tussock

Scientific Name:

Nassella trichotoma

Alternative common names:

Serrated tussock.


Nassella tussock is a weed of regional and national significance because of its invasiveness, destruction of pastures, negative impacts on biodiversity and difficulty to control. It can reach up to 30cm tall and has thin, tightly rolled, hairless, yellow-green leaves with very fine serrations. Young flower heads have a purple tinge and turn golden as seeds ripen. These weeping flower heads break off at maturity. It generally flowers during mid to late spring, and the seeds develop in early to midsummer.

Additional Information

Where does this species come from?

Argentina, Uruguay, Chile and Peru.

What is its invasive status in South Africa?

NEMBA Category 1b.

Where in South Africa is it a problem?

Western Cape, Eastern Cape, Limpopo, Gauteng, Free State and Mpumalanga.

How does it spread?

The seeds are prolific, have an extensive life and spread via wind, causing a significant and ongoing risk to agriculture and the natural environment.

Why is it a problem?

It can completely replace natural veld that has been disturbed as well as nutritive grazing land. It can also reduce the carrying capacity of the land. Death of animals is caused when nassella fibres cannot be digested and completely block the gut. The sharp seed awns can penetrate the skin, causing severe irritation to the skin of young lambs. It thrives under a wide range of climatic, soil and topographic conditions, and threatens not only agriculture, but also indigenous fauna and flora. This threatens the biodiversity of many indigenous vegetation communities, including grasslands, grassy woodlands and some coastal vegetation.

What does it look like?

Leaves: Tightly rolled, narrow, stiff and upright.

Flowers: Flowering occurs mostly during late spring and summer.

Fruit/seeds: Seeds are hard and small, 1.5mm long, with a ring of white hairs at one end and a twisted awn, 25mm long at the other. During flowering, the seed is encased in reddish-brown or purple bracts.

Does the plant have any uses?

Used to prevent soil erosion.

Leave a Reply