Burdock

General description

Bushy, much-branched, thistle-like biennial forb < 1.5m tall. Leaves are < 50 cm long. Flowers are spiky green spheres with pink/purple centres and bracts that become hooked when dry, and are borne January – April. Seeds are attached to pappus.

What you need to know

To help protect our environment:

• You must not breed, distribute, release or sell burdock within the Auckland region.
You must not plant burdock within the Auckland region, unless you are transferring an existing plant on your land to another location within the boundaries of the same property.
• You must destroy any burdock 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

Forest margins, scrub, creek beds, pasture, gardens, wasteland, open and disturbed sites.

Dispersal

Seeds dispersed by wind, water, attachment to animals and humans.

Impact on environment

Burs contaminate sheep wool and injure livestock. Taints milk if foraged in large quantities. Reservoir for fungal diseases that could impact horticultural plants. Can cause contact dermatitis and toxic seed hairs may be irritating to pets and humans.

Control

Site Management

Maintaining good pasture cover will suppress an infestation. Mowing before flowering will reduce spread of burs. Control is most effective on first year rosettes.

Recommended approaches

Physical control

Method: Dig out.

Plant parts requiring disposal: Seeds (burs).

Disposal options: Remove to greenwaste or landfill if practical.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

No qualifications: Foliar spray with 100ml glyphosate green per 10L of water.

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