Koster's curse (Clidemia hirta)
PROHIBITED MATTER: If you see this plant report it. Call the NSW DPI Biosecurity Helpline 1800 680 244
Also known as:
clidemia, soapbush, hairy clidemia
Koster’s curse is an invasive shrub with bright green leaves and hairy berries. It forms dense thickets and invades forests, plantations and pastures.
Profile
How does this weed affect you?
Koster’s curse spreads quickly and:
- forms dense thickets
- invades forests and smothers native plants
- outcompetes pastures reducing production
- invades plantations.
It has the potential to cause widespread damage to sensitive ecosystems as it can grow in under the canopy of undisturbed rainforests.
Animal health
Koster's curse contains tannins which could cause damage to kidneys and the gastrointestinal tract of horses and ruminants (e.g. cattle and sheep). No incidents have been recorded in Australia.
What does it look like?
Koster’s curse is a bushy perennial shrub covered in reddish-brown bristly hairs. It usually grows to around 2 m high, although it can grow up to 5 m in moist, shady conditions.
Leaves are:
- bright, shiny green on top
- lighter green underneath
- 5–14 cm long and 4–7 cm wide
- oval-shaped with a pointed tip and finely toothed edges
- prominently veined with five veins running long ways down the leaf and lots of cross veins giving a wrinkled look
- covered with stiff hairs
- in opposite pairs along the stem.
Flowers are:
- white or pinkish with 5 petals
- 0.5–1.5 cm in diameter
- in clusters of 6–20 in the leaf forks or at the end of branches
- present all year except in dry conditions.
Fruit are:
- a berry
- reddish-purple ripening to dark purple, dark blue or black when mature
- 4–9 mm in diameter
- covered in stiff, reddish-brown hairs
- filled with up to 800 seeds 0.5–0.6 mm long.
Stems are:
- round in cross section
- covered with stiff brown or reddish hairs.
Roots are:
- lateral and abundant
- shallow
- fine.
Similar looking plants:
Koster's curse looks similar to:
- Blue tongue (Melastoma affine),which is a native plant with larger flowers. It has round, purple to pink (rarely white) petals up to 2 cm long. The leaf edges are smooth rather than toothed.
- Asian Melastome (Melastoma candidum), which is an introduced species. Its leaves usually have 7 (rather than 5) veins running long ways down the leaf. The leaves have smooth edges. Its flowers are purple with petals up to 3 cm long.
Where is it found?
Koster’s curse has not been found in New South Wales but it has the potential to invade northern coastal areas.
Australia’s first infestation was found in 2001 in north Queensland. It may have entered the country through contaminated packaging material.
Koster’s curse comes from Central and South America. It is a weed in parts of Asia, Africa and many Indian Ocean islands and tropical Pacific islands.
What type of environment does it grow in?
Koster's curse prefers humid tropical climates with annual rainfall over 1200 mm. It grows in shade and full sun. It spreads quickly in disturbed areas including along:
- roadsides and paths
- edges of forests
- fence lines
- streambanks.
Koster’s curse can also invade undisturbed forests including under dense rainforest canopy.
Maps and records
-
Recorded presence of Koster's curse during property inspections (Map: Biosecurity Information System - Weeds, 2017-2023)
These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
How does it spread?
By seed
Plants can mature and set seed in less than a year. In ideal conditions, each plant can produce 700 000 seeds per year and seeds can remain viable in the soil for at least 8 years.
Most seeds are dispersed by birds that eat the fruit. It may also be spread by other animals including feral pigs. Seeds can be spread long distances by flood waters or in contaminated soil on footwear or on tyres.
By plant parts
Koster’s curse can also grow from cuttings, detached leaves and stems.
References
Hosking JR, Sainty GR, Jacobs SWL & Dellow LL (in prep) The Australian WeedBOOK.
McKenzie, R. (2012). Australia's poisonous plants, fungi and cyanobacteria: a guide to species of medical and veterinary importance. CSIRO.
Queensland, Department of Agriculture and Fisheries (2020). Restricted invasive plant: Clidemia hirta. Retrieved 12 August 2020 from: https://www.daf.qld.gov.au/__data/assets/pdf_file/0003/337701/kosters-curse.pdf
Queensland Government (2016) Weeds of Australia Biosecurity Queensland edition, Fact sheet: Clidemia hirta. Retrieved July 2020 from:https://keyserver.lucidcentral.org/weeds/data/media/Html/clidemia_hirta.htm
Waterhouse, B. M. (2003). Know your enemy: recent records of potentially serious weeds in northern Australia, Papua New Guinea and Papua (Indonesia). Telopea, 10(1), 477-485.
More information
Control
Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately.
NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading.
Herbicide options
WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
See Using herbicides for more information.
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 200 g/L
(Comet® 200 herbicide)
Rate: 500 mL to 1 L per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock feed for 7 days after application. See label for further information.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Fluroxypyr 333 g/L
(Starane™ Advanced)
Rate: 300 to 600 mL per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock food for 7 days after application. See label for more information.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L
(Various products)
Rate: One part product to 20 parts water
Comments: Wipe onto leaves
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg
(Various products)
Rate: 10 - 20 g per 100 L water plus surfactant
Comments: Spot spray
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: B, Inhibitors of acetolactate synthase (ALS inhibitors)
Resistance risk: High
PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg
(Various products)
Rate: 10 g per 1 L of water plus surfactant
Comments: Wipe onto leaves
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: B, Inhibitors of acetolactate synthase (ALS inhibitors)
Resistance risk: High
Biosecurity duty
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
| Area | Duty |
|---|---|
| All of NSW | General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
| All of NSW |
Prohibited Matter
A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries |
For technical advice and assistance with identification please contact your local council weeds officer.
Reviewed 2020
