(Also known as Vipers Bugloss, Italian Bugloss)
Type of weed: With underground regrowth structures
Flower colour(s): Blue-purple, Purple
Priority Weed Local Priority Weed. (See more weeds of the Local Priority Weed class.)
Flowering Months: September, October, November, December
A winter annual herb with hairy leaves and stems.
Flowers generally appear from September to December and are deep blue to purple, 20–30 mm long, with five petals fused into a trumpet shape.
- Some people are allergic to the pollen. The rough, hairy texture of the leaves and stems may cause skin irritation in people having close contact with the plant.
- Paterson’s Curse is poisonous to livestock.
Roughened seed coats allow seed to adhere to wool, fur and clothing. Viable seed is spread by animals that have been feeding on the weed. Seed can also be carried by water runoff or dispersed in contaminated hay and feed grain.
Impact on bushland
Paterson’s Curse often becomes the dominant species in pastures. It is a prolific seeder that can produce more than 5000 seeds per plant per year. It degrades the natural environment, compromising habitat values by crowding out and suppressing native vegetation.
Lower Blue Mountains, Upper Blue Mountains. Mainly in Megalong Valley.
Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.
There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.
- Hand remove
Grasp stem at ground level. Rock weed backwards and forwards to loosen roots, then pull out gently. Carefully tap the roots to dislodge attached soil. Replace disturbed soil and pat down.
- Leave weeds so that roots do not make contact with soil; on a rock, for instance. A small amount of debris may be hung in a tree or removed from the site.
- Vary the position of your body to avoid fatigue when removing plants by hand over extended periods.
Note: Herbicides that may be used for this weed include Picloram, Triclopyr.
Please consult the Herbicide page of this website to help you decide whether to spray, how to do it safely and more.
Extra considerations for weeds with underground reproductive structures
- Further digging may be required for plants with more than one tuber. Some bulbs may have small bulbils attached or present in the soil around them. These need to be removed. It may be quicker and more effective to dig weeds out.
- Learn and understand how the herbicide works. For bulb and corm species the most effective time is after flowering and before fruit has set.
Specific control tips for this weed
- For small infestations, single plants and small patches can be controlled by hand removal, but all roots must be removed or the plant will regenerate. Use a trowel to loosen the soil first.
- For dense areas of Paterson’s Curse, including regrowth where there are no native plants, spraying is the most effective treatment. Recommended mixture: Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L.
- For infestations on rural properties, please refer to Council’s Weed Management Plan for Paterson’s Curse.
- Spraying should not be used in areas where off-target damage is likely to occur.
See the NSW Department of Primary Industries WeedWise website for more information.
For key points on these techniques:
Local Priority Weed
- The plant should be fully and continuously suppressed and destroyed.
- Plants under 4 metres in height should be fully and continuously suppressed and destroyed.
- The spread of this plant should be adequately contained to prevent spread impacting on priority assets. Weed notices will only be issued for these weeds under special circumstances.