Siberian lyme grass

What does it look like?

Siberian lyme grass is a perennial grass that grows in large, dense clumps and can reach up to 1.5 metres tall. It spreads through thick underground stems, which help it form very robust tufts.

The leaves are stiff and strongly ribbed, with little to no hair, and the leaf sheaths are yellowish and mostly smooth. In summer, the plant produces a tall, upright flowering spike that is stiff, narrow and tapered, measuring around 25 to 40 centimetres long. The seeds are small and narrow.

Why is it a problem?

It was first introduced into New Zealand for agriculture and was first reported growing outside cultivation in 1895. Siberian lyme grass invades coastal dunes, foreshore areas and other sandy places forming a dense monoculture, completely replacing other species in the area.  

Control methods

Physical control is not effective because new plants sprout from rhizomes and root fragments left in the soil.

Herbicide control:

• Treat stems with a glyphosate-based solution in early spring before other native species emerge.
• Grass specific herbicides can be used but may also kill native grasses. Repeated applications may be necessary to kill all plants.

More information

• This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by the Department of Conservation.
• This plant is not known to exist in Hawke’s Bay. We would like to be informed of any sightings. If you see this plant, please contact us on 06 835 9200.

Related links

NZPCN listing