Persicaria capitata

Pink-head knotweed

Family: Polygonaceae

Origin: Asia

Close up of pink headed knotweed flowers.
A popular garden plant for its red and green patterned leaves and pink snowball flowers. Considered a ground cover this knotweed can form dense mats throughout gardens and invade into native bush.
Photo credit: Jonathan Boow

Regional Pest Management Plan (RPMP) status

  • Not a legally declared pest

View more about the RPMP statuses

General description

Trailing evergreen perennial herb that has a urine-like odour. Stems are long and slender. Leaves are < 6 cm long, ovate and alternate, with a reddish, hairy midrib and 'V' pattern. Flowers are pink and borne in ball-like inflorescences in October – March.

What you need to know

Although pink-head knotweed is not a legally declared pest plant, it may still be invasive in some situations. Consider lower risk alternatives for your garden, such as native plants.


Open areas, dry banks, rocky areas.


Sets seed. Vegetative spread from trailing stems. Human-mediated dispersal through dumping of garden waste.

Impact on environment

Forms dense mats, displacing native vegetation.


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 is currently not available for this species.

Community agrichemical control recommendations

No qualifications: Foliar spray with 10ml glyphosate green per 1L of water.

Basic Growsafe certified: Foliar spray in summer with 100ml glyphosate green per 10L of water.

Certified Handler/Experienced agrichemical user: Foliar spray with 200ml glyphosate green and 3g metsulfuron-methyl per 10L and 20ml penetrant.

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

A hand holding a stalk of pink headed knotweed leaves.
Stems are covered in many fine hairs and are slightly woody and tough to break. Not declared a pest plant in Auckland but has the potential to become weedy..
Photo credit: Jonathan Boow
A wall of pink headed knotweed.
The flowers can be pollinated and set viable seed. This knotweed is generally spread through vegetation means from plant stems, and can regrow if dumped on the roadside.
Photo credit: Jonathan Boow