Red cestrum (Cestrum elegans)

Also known as: elegant poison berry

Red cestrum is a hairy shrub with small red tubular flowers. All parts of the plant are poisonous to people and animals.

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How does this weed affect you?

Red cestrum forms dense thickets. It:

• is poisonous to people, pets, livestock and native animals
• can cause skin rashes
• outcompetes native plants
• reduces food and shelter for native animals
• may reduce livestock productivity when infested pastures cannot be grazed due to poisoning
• can restrict movement of people and animals.

Other Cestrum species

Green cestrum (Cestrum parqui) and Lady of the night (Cestrum nocturnum) are also poisonous cestrum weeds. For information about these weeds use the WeedWise search functions.

Human poisoning

All parts of the plant are toxic, especially the berries.  Avoid touching the plant with bare skin and if the plant is accidentally touched wash the skin thoroughly.

What to do if a person is poisoned:

• If the patient is unconscious, unresponsive or having difficulty breathing dial 000 or get to the emergency section of a hospital immediately.
• If the patient is conscious and responsive call the Poisons Information Centre on 13 11 26 or your doctor.

Animal poisoning

Red cestrum contains alkaloids that are poisonous and can cause animal deaths.  Plants are poisonous to livestock including cattle and horses.

Remove livestock from paddocks when controlling red cestrum. Do not return livestock until plants have disintegrated or been removed.

What does it look like?

Red cestrum is a perennial shrub up to 5 m tall. It can be either single or multi-stemmed at the base. Most parts of the plant are covered with fine purple hairs.

Leaves are:

• dull green on top and paler green on the underside
• oval to spear shape with pointed tips
• 7–11.5 cm long, 2.5–5.5 cm wide
• hairy all over when young and then just on the veins when older
• on a stalk up to 1.5 cm long
• alternate along the stem
• smell foul when crushed (caution wear gloves when handling plants).

Flowers are:

• pinkish red to pinkish purple 
• tubular shaped with five triangular lobes at the end
• up to 23 mm long and up to 5 mm wide
• in tightly packed clusters 
• mostly present from winter to spring.

Fruit are:

• red or pink berries
• rounded
• 6–13 mm diameter.

Stems are:

• branched
• hairy with purple hairs when younger
• woody when older.

Similar looking plants

Red cestrum looks similar to early flowering jessamine (Cestrum fasciculatum), which has larger flowers. There are also hybrids of red cestrum and early flowering jessamine.

Where is it found?

In NSW, red cestrum has been found in:

• the South East region near Wollongong and the southern highlands
• the North Coast region near Bellingen and Port Macquarie
• Newcastle in the Hunter region
• several locations in Greater Sydney.

Red cestrum is native to southern Mexico.

What type of Environment does it grow in?

Red cestrum can grow in a wide range of climate and soil conditions. It is drought tolerant and grows in shade and full sun. It has been found growing along rainforest edges, in wet sclerophyll forests, along waterways and in paddocks.

Maps and records

• Recorded presence of Red cestrum 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?

Red cestrum has been planted in gardens as an ornamental plant.

By seeds

Red cestrum can start producing seeds when it is less than a year old. Each plant can produce up to 1500 seeds per year and the seeds can remain viable for up to 8 years. Birds eat the fruit and spread the seed in their droppings. If plants are on the edge of waterways the seeds spread downstream. Seeds could also be spread in contaminated soil or mud. 

By plant parts

Red cestrum can grow from stem and root fragments which can be spread by garden dumping. The plants sucker readily, which quickly increases the size of the infestations.

References

Colorado State University (2021). Guide to poisonous plants. Retrieved 23 November 2021 from: https://csuvth.colostate.edu/poisonous_plants/Plants/Details/121.

Identic and Lucid (2016). Weeds of Australia: Cestrum elegans (Brongn. ex Neumann) Schltdl. Retrieved 23 November 2021 from:https://keyserver.lucidcentral.org/weeds/data/media/Html/cestrum_elegans.htm#Naturalised%20Distribution

Muyt, A. (2001). Bush invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South-East Australia. RG and FJ Richardson.

NZ Weedbusters (2021) Weed information sheet: Red cestrum. Retrieved 23 November 2021 from: https://www.weedbusters.org.nz/what-are-weeds/weed-list/red-cestrum/

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 22/11/2021 from https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Cestrum~elegans

Stewart-Howie, M. (2003). Environmental weed treatment in Melbourne's water catchment. Plant Protection Quarterly, 18(2), 70-71.

VicFlora (2016). Flora of Victoria, Royal Botanic Gardens Victoria, Retrieved 23 November 2021 from: https://vicflora.rbg.vic.gov.au/flora/taxon/b390b014-45ca-49e7-a291-ef43948b2b2d

More information

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Control

Successful weed control relies on follow up after the initial efforts. This means looking for and killing regrowth or new seedlings. Using a combination of control methods is usually more successful.

Wear gloves and other personal protective clothing when controlling red cestrum to prevent coming into contact with the plant.

To manage red cestrum:

• control young plants before they mature
• treat mature plants before they flower
• control regrowth from treated plants
• keep checking for new seedlings for many years because seeds can remain dormant in the soil.  

Hand removal

Seedlings can be pulled or dug out when small. Larger plants are difficult to remove due to their extensive roots and because it is difficult to limit contact with the larger plants. Dispose of plants carefully as stems can reshoot if left touching the soil. 

Disposal

Contact your local council for advice on how to dispose of this poisonous plant.

Chemical control

Spraying

Spray actively growing plants and ensure that all the foliage is covered with the herbicide. Keep stock away from dead plant material as it remains poisonous. 

Cut and paint

Cut the stem and apply herbicide within 15 seconds of cutting. Dispose of the cut part of the plant carefully as stems can reshoot if left touching the soil. 

Herbicide options

See Using herbicides for more information.

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: Up to 1:50 herbicide to water.
Comments: Spot spray. See permit for additional conditions.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: 1:1.5 with water to undiluted herbicide.
Comments: Cut, scrape and paint. See permit for additional conditions.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon Extra®)
Rate: 500 mL per 100 L of water
Comments: Apply from late spring to early autumn. Any regrowth and seedlings should be resprayed when 1 m high. Follow the label instructions for green cestrum.
Withholding period: Where product is used to control woody weeds in pastures there is a restriction of 12 weeks for use of treated pastures for making hay and silage; using hay or other plant material for compost, mulch or mushroom substrate; or using animal waste from animals grazing on treated pastures for compost, mulching, or spreading on pasture/crops.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Picloram 44.7 g/L + Aminopyralid 4.47 g/L (Vigilant II ®)
Rate: Undiluted
Comments: Cut stump application. Apply a 3–5 mm layer of gel for stems less than 20 mm. Apply 5 mm layer on stems above 20 mm .
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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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.
North Coast	Regional Recommended Measure* (for Regional Priority - Eradication) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
Northern Tablelands	Regional Recommended Measure* (for Regional Priority - Prevention) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2023