Gunnera manicata

Giant rhubarb

Family: Gunneraceae

Origin: Brazil

Close up of giant rhubarb leaves.
Giant rhubarb can grow up to 2.5m tall and 4m wide.
Photo credit: Antonie van den Bos,

Regional Pest Management Plan (RPMP) status

  • Whole region — Sustained control
  • Hauraki Gulf Controlled Area Notice pest

View more about the RPMP statuses

General description

Clump-forming perennial herb < 2.5 m tall, < 4 m wide. Rhizomes are stout. Leaves are very large and prickly. Flowers are minute and borne on dense, closely branched conical panicles < 1 m long. Drupes contain a single ovoid, flanged seed.

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 giant rhubarb within the Auckland region.
  • will not be allowed to plant giant rhubarb 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 giant rhubarb 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.


Riparian margins, wetlands, coastal areas, cliffs.


Sets seed. Vegetative spread from rhizome fragments.

Impact on environment

Competes with native vegetation and prevents native seedling establishment. Reduces native biodiversity in riparian margins, wetlands, coastal areas and cliffs.


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: Seeds and rhizomes.

Disposal options: Remove to greenwaste or landfill.


Biocontrol is currently not available for this species.

Community agrichemical control recommendations

No qualifications: Cut stump and paste freshly cut base of stems with double strength glyphosate gel
or cut stump and spray freshly cut base with 200ml glyphosate green per 1L of water.

Certified Handler/Experienced agrichemical user: Foliar spray with 200ml glyphosate green per 10L of water and 20ml penetrant.

Safety notes

Plant has spines.

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

Two types of giant rhubarb flowers lying side by side with their scientific names next to it.
Giant rhubarb has large flower spikes that are up to 1 m tall with tiny flowers and fruit covering the spike.
Photo credit: Antonie van den Bos,
Close up of giant rhubarb stem and leaf.
Leaves are large and prickly.
Photo credit: C. Howell, Department of Conservation