St John's wort (Hypericum perforatum)

Weed control program

Section 371 (1) b of the Biosecurity Act 2015

This Weed Control Program is a Council endorsed document under Section 371 (1) (b) of the Biosecurity Act 2015 and describes how a person must discharge the person’s general biosecurity duty for the biosecurity matter (weed) described.

Plant species

Common name: St John's wort
Scientific name: Hypericum perforatum

Area of operation

Local government area of Eurobodalla Shire.

Species information

An erect branched perennial herb, with small light green to blue-green leaves, arranged in opposite pairs. If the leaves are held up to the light, fine translucent oil dots can be seen in them. Yellow flowers also have the oil dots, and appear in mid-summer, and the plant dies back to the rootstock over winter and does not begin growing again until early summer.

At some times of year, the growth habit of non-flowering stems may be prostrate and ground-hugging. The seeds are in papery capsules which dry to dark brown. Found in pasture and on road verges, generally in drier parts of the region. St John’s wort is more common on the tablelands and slopes, where it is a major weed of grazing land, and a serious environmental weed of remnant grassy native vegetation.

The plant is poisonous to stock, dry or fresh, causing photosensitisation in pale coloured animals. The faces and mouths become itchy and raw, preventing feeding.

Seed sticks to animals or vehicles, or is spread in contaminated soil. It can be introduced in contaminated hay or chaff. Each plant also spreads via underground runners. These can be chopped up and spread during cultivation. Seed is long-lived in the soil and each mature plant produces up to 30,000 seeds per season.

Legal obligations

Any person who deals with biosecurity matter or a carrier and who knows, or ought reasonably to know, the biosecurity risk posed or likely to be posed by the biosecurity matter, carrier or dealing has a biosecurity duty to ensure that, so far as is reasonably practicable, the biosecurity risk is prevented, eliminated or minimised.

Weed risk assessment

Risk level: Medium
Impacts: Economy 
Control objective: Containment

Council control requirements

  1. The plant must be destroyed.
  2. Slashing is not a control method.
  3. The plant must not be grown, propagated or distributed.


A person who fails to discharge the person’s general biosecurity duty is guilty of an offence.

In the event that the general biosecurity duty is not discharged, Council may:

  • charge a reinspection fee
  • issue a fine notice (refer to Biosecurity Regulation 2017 (NSW) Schedule 6 - Penalty notice offences)
  • enter the property, perform weed direction works, and recoup all costs and expenses incurred.

Review date

When required.

Contact details

Invasive Species Supervisor - Biosecurity Act 2015 Authorised Officer
PO Box 99
Moruya NSW 2537

T: 02 4474 1000