Paspalum vaginatum

Salt water paspalum

Family: Poaceae

Origin: North and South America

Salt water paspalum in front of some rocks.
Leaves are grey-green and leathery. Bears flowers in summer.
Photo credit: Jeremy Rolfe

Regional Pest Management Plan (RPMP) status

  • Hauraki Gulf Controlled Area Notice pest
  • Parkland with Significant Ecological Areas — Site-led
  • Waitākere Ranges Heritage Area priority status
  • Whole region — Sustained control

View more about the RPMP statuses

General description

Terrestrial to emergent aquatic decumbent perennial grass. Stolons are long, creeping and form adventitious roots from nodes. Leaves are leathery, grey-green and < 80 x 20 cm long. Flowers borne in summer.

What you need to know

To help protect our environment, from 1 September 2021, you:

  • will not be allowed to breed, distribute, release or sell salt water paspalum within the Auckland region.
  • will not be allowed to plant salt water paspalum within the Auckland region, unless you are transferring an existing plant on your land to another location within the boundaries of the same property.
  • must destroy any salt water paspalum on land that you occupy if it has been planted in breach of the above rules and you are directed to do so by an authorised person.

Habitats

Brackish water, mudflats, mangroves, salt marshes, coastal turfs, riparian and estuarine margins, sand dunes, shingly shores, pastures, shrubland, roadsides.

Dispersal

Sets seed. Vegetative spread from stolons, dispersed by water and sand movement and contamination of machinery and livestock.

Impact on environment

Forms dense mats, excluding native vegetation, altering plant community composition and dominating high priority ecosystems. Can displace burrowing fauna and shift invertebrate assemblages. May alter foraging habitat and food availability for shore birds and spawning and feeding grounds for fish.

Control

Site Management

Follow up treated areas 3 times per year. Encourage natural regeneration of native plants or replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.

Recommended approaches

Physical control

Method: Dig out.

Plant parts requiring disposal: All parts.

Disposal options: Remove to greenwaste or landfill.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

Certified Handler/Experienced agrichemical user: Foliar spray with 100ml glyphosate green per 10L of water.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Crawling vines of salt water paspalum in the sand.
Also know as siltgrass or seaside millet among other names. It is a semi-aquatic plant that grows above mid-tide level of tidal waters.
Photo credit: Jeremy Rolfe
Close up shot of salt water paspalum between two rocks.
Long creeping grass that forms dense mats. An aquatic plant that can grow in salt water.
Photo credit: Jeremy Rolfe
Close up on salt water paspalum seeds.
Pale, papery leaves appx 1-2mm in width. Plant spreads by underground stolons that can pop up nearby and continue to grow.
Photo credit: Jeremy Rolfe