08/12/2021
W**D OF THE WEEK – ST JOHN’S WORT
We’re into week six of our W**d of the Week campaign, continuing to share important information on our region’s priority w**ds. This week we’re looking at St John’s Wort.
We encourage our community to get to know our region’s unwanted (priority) w**ds. Knowing what to look for and how to help, we can work together protect the environment, help our farmers and support our community.
The impact of w**ds on natural vegetation can be devastating and is estimated to cost the NSW economy approximately $1.8 billion annually (NSW Department of Industry, 2018).
What is St John’s Wort?
St John’s Wort (Hypericum perforatum) is an exotic, perennial, woody w**d with perforated leaves and yellow flowers. It grows to about 30 – 90cm tall. Wort spreads via seed as well as underground runners and is very difficult to manage.
Why is St John’s Wort a problem?
• In extreme cases it can be toxic to stock and can cause photosensitisation (resulting in sunburn), failure to thrive, abortion and even death if grazed extensively by susceptible stock.
• St John’s Wort is a priority w**d in the Snowy Monaro Regional Council area due to its toxic potential and invasiveness. This w**d can be found along the road corridor, on lands around towns, on ungrazed farmland and on many rural properties.
• St John’s Wort will also readily invade bushland – including native grassland, woodland and forested areas – competing with native vegetation and reducing biodiversity.
• St John’s Wort spreads quickly through paddocks and along tracks and trails. It invades both native vegetation and improved pasture.
• Seeds stick to fleece and fur and can reduce wool quality.
• Vehicles, equipment, livestock and native animals can all spread seeds.
What can you do?
• Learn to identify and effectively control St John’s Wort in its early stages of invasion.
• Search your property for new germinations or regrowth of St John’s Wort. Plants are more obvious from early December when they begin flowering. You can find new leaves emerging from October. If you find plants, control them prior to the flowers forming capsules as this will prevent seed set.
• Avoid the use of non-selective herbicides which will destroy beneficial vegetation surrounding St Johns Wort plants. Maintaining a strong, competitive pasture is essential to every w**d control program.
• Like many w**ds, a well-managed, intensive grazing program can provide very effective control of St Johns Wort. Carefully consider your standard of fencing and livestock susceptibility before embarking on this adventure.
• Biological controls, including Chrysolina beetles, Gall midge (Zeuxidiplosis giardi), Green aphid (Aphis chloris) and St John’s wort stunt mite (Aculus hyperici) can be effective in controlling St Johns Wort in some situations. Seek advice before employing biological controls.
• Dispose of any plants you remove manually on-site or in the designated W**ds bins at a Council Landfill. Do not dispose of plant waste in your local park or reserve.
• Download the free NSW W**dWise app for detailed information on how to identify and manage local priority w**ds: https://www.dpi.nsw.gov.au/biosecurity/w**ds
• Visit Council’s website to understand how we can help you with w**d management: https://www.snowymonaro.nsw.gov.au/140/Biosecurity-and-W**ds
• Visit the Department of Primary Industries (DPI) website for information on w**d control methods: https://www.dpi.nsw.gov.au/biosecurity/w**ds/w**d-control
Contact us if you have any questions regarding St John’s Wort or any other w**ds on your property. Call 1300 345 345 to be connected to our Biosecurity Officers who specialise in w**d management.
