Blue heliotrope (Heliotropium amplexicaule)

Blue heliotrope is a summer-growing perennial herb. It is extremely drought-hardy, which makes it a major agricultural weed in NSW.

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How does this weed affect you?

Blue heliotrope is widespread in NSW and it:

• competes with native and improved pastures, reducing productivity
• competes with crops including cotton and sugar cane, reducing productivity and contaminating produce
• outcompetes native plants especially in woodlands and grasslands
• contaminates honey if bees collect from the flowers
• is poisonous to livestock and people.

Human poisoning

Blue heliotrope contains pyrrolizidine alkaloids, which are poisonous to people. It is unlikely to be eaten directly, but the toxins can be present in honey from blue heliotrope flowers.

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.

Livestock poisoning

All the above ground parts of blue heliotrope plants contain pyrrolizidine alkaloids, which are toxic to livestock. It is not very palatable, and livestock usually avoid eating it unless there is no other feed available. Horses and cattle are the most likely to be poisoned.

Poisoning symptoms vary between species:

• Horses suffer liver and secondary brain damage. Symptoms include weight loss, depression, respiratory difficulties, loss of coordination and they may wander aimlessly.
• Cattle may suffer liver and brain damage. They become depressed and can have unpredictable bouts of aggression.
• Sheep and goats are more resistant to poisoning but will be affected by large or prolonged intake. Sudden death can occur under stressful conditions such as movement or cold weather.
• Pigs suffer liver, kidney and lung damage and death. They are very susceptible but unlikely to eat it.
• Poultry are very susceptible to the toxin.
• Alpacas and donkeys have a substantial risk of poisoning.

What does it look like?

Blue heliotrope is a low growing or creeping perennial herb. It grows 15–30 cm tall and 30–200 cm in diameter. Plants die off in winter and regrow from the roots in spring. In frost-free areas, it can grow and flower at any time of the year when conditions are suitable.

Leaves are:

• dull to dark green
• 2–9 cm long and 0.4-2.5 cm wide
• oblong or lance shaped and tapered at both ends
• soft and hairy with wavy margins and sunken veins
• mostly stalkless and sometimes clasp the stem
• alternate along the stem.

Seedling leaves grow in a rosette.

Flowers are:

• blue, purple, lilac, or pink, with yellow centres
• tubular with 5 fused petals, which are surrounded by 5 green leaf-like sepals
• 3-6 mm long and 3-6 mm wide
• in dense clusters, of 2 rows along one side of a coiled stalk
• usually present in late spring and continuing through summer.

Fruit are:

• green and round, held inside the green leaf-like sepals at first
• dark brown or black, rounded, warty and wrinkled when mature
• made up of two segments (nutlets), 2–3 mm long, that separate when mature, each contains 1 or 2 seeds.

As the fruit ripens the stems straighten.

Seeds are:

• black
• rounded.

Stems are:

•  dull green and hairy
• up to 1 m long
• cylindrical in cross section
• multi-branched, radiating from a central woody root
• highly aromatic when damaged and may smell like passionfruit.

Roots include:

• a slender, woody taproot that can grow 1–3 m deep 
• many lateral roots (up to 3 m long) extending out from the taproot.

Similar looking plants

Young plants in the rosette stage look like Paterson’s curse (Echium plantagineum), which grows up to 120 cm tall and has larger leaves (up to 30 cm). Its flowers are larger, up to 3 cm long.

Where is it found?

Blue heliotrope grows in all regions of NSW and is most widespread in central NSW. The first report in NSW was in 1908 in the Hunter Valley.

Blue heliotrope is native to South America and it is likely that it was introduced as an ornamental in the late nineteenth century.

What type of environment does it grow in?

Blue heliotrope grows best in warm temperate and subtropical climates with more than 500 mm of annual rainfall. Plants are drought and shade tolerant but do not tolerate water logging. In areas that have frost, plants die back in winter. Seedlings can survive frost if protected by other plants.

Plants can grow in a wide range of soil types, including infertile soils and highly acidic soils. Generally, it grows best in sandy or red loam soils.

Blue heliotrope grows:

• in pastures, especially if degraded 
• along roadsides and other disturbed areas such as cultivated fallows
• in woodlands and grasslands
• along waterways and drainage lines
• in parks and gardens.

Maps and records

• Recorded presence of Blue heliotrope during property inspections (Map: Biosecurity Information System - Weeds, 2017-2026)
  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

Seeds germinate in warm, wet conditions and can flower within 2–3 months from seedling emergence. Blue heliotrope infestations have been recorded with up to 50 000 seeds per m2 in the soil seed bank. Buried seeds can survive in the soil for over 10 years.

Seeds spread:

• by sticking to animal fur, wool and hooves
• by animals eating seeds
• by sticking to machinery and vehicles
• in bales of hay and fodder
• in moving water.

By plant parts

New blue heliotrope plants can grow from root fragments. Fragments are spread by earth moving equipment, farm machinery, livestock and flowing water, especially in flood events.

References

da Silva, E. (1991). The ecology and control of blue heliotrope (Heliotropium amplexicaule Vahl.). Project DAN 35. Final report for the Wool Research and Development Corporation. New South Wales Agriculture, Trangie, NSW

Identic Pty Ltd. and Lucid (2016). Environmental Weeds of Australia Fact sheet: Heliotropium amplexicaule Vahl. Retrieved: 21 October from: https://keyserver.lucidcentral.org/weeds/data/media/Html/heliotropium_amplexicaule.htm

Parsons, W.T., & Cuthbertson, E. G. (2001). Noxious weeds of Australia. 2nd edition. CSIRO publishing.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 21 October 2025 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Heliotropium~amplexicaule

Potter, S., Sheehan, M.R. and Virtue, J.G. (2023). A best practice manual for managing blue heliotrope (Heliotropium amplexicaule) in NSW. New South Wales Department of Primary Industries, Orange, NSW.

Roberts, J., Peerzada, A. M., & Bajwa, A. A. (2024). Biology, ecology, impacts and management of the invasive weed, blue heliotrope (Heliotropium amplexicaule Vahl)—A review. Sustainability, 16(14), 5923.

More information

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Control

Successful weed control requires 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.

Prevention

To prevent spreading blue heliotrope:

• Avoid bringing in contaminated fodder and monitor feed-out areas for new weeds. You can request a vendor declaration to ensure fodder is weed free.
• Hold new stock before release to clean paddocks. Monitor and control weeds emerging in the holding area.
• Clean equipment, including vehicles, before moving from an infested area to an un-infested one.
• Do not make hay or silage from paddocks with blue heliotrope.

By hand

Seedlings and small plants can be hand pulled. This is easiest when the soil is moist. Hold the stem as close as possible to the base of the plant, then gently tug the stem from side to side to loosen the soil before pulling. Dig out the roots if they break. Wear gloves when handling blue heliotrope.

Larger plants can be dug out, though this is very time-consuming and the roots may be deep. Dispose of plant parts carefully.

Disposal

Contact your local council for advice on how to dispose of blue heliotrope.

Pasture management

Establishing and maintaining locally adapted perennial pastures can help out-compete blue heliotrope. Maintaining healthy soil will help the pastures to compete with the weeds. Try to maintain ground cover and avoid overgrazing, especially in summer when blue heliotrope seedlings sprout.

Cultivation

Cultivation may stimulate the germination of buried seeds and spread root fragments. Do not cultivate seeding plants. In spring and summer, cultivation can be used to treat seedlings. When cultivating adult plants, it is best to kill the plants with herbicide prior to cultivation to avoid spreading viable root fragments.

Follow up cultivated sites with herbicide to treat new seedlings.

Biological control

The blue heliotrope leaf-beetle (Deuterocampta quadrijuga) was released in Australia in 2001. The larvae and adults feed on leaves. They prefer areas with mild summers and high rainfall and are now widespread in higher rainfall areas of NSW. In high densities, the beetles can completely defoliate plants but are unlikely to give sufficient control without other methods.

Multiple, short-interval releases are needed to establish a large population of beetles. The release sites may need watering in drier seasons so the beetles can establish. Once established, populations can grow quickly as each beetle lays several hundred eggs.

Research into a second agent, the root-feeding flea-beetle, is occurring, but the flea-beetle is not yet approved for release in Australia.

Contact your local council weeds officer for more information about using biological control for blue heliotrope.

Chemical control

Spraying

Spray when plants are actively growing and thoroughly cover all the foliage. Seedlings are easier to kill than mature plants. Check the herbicide labels and permits for the best time to spray blue heliotrope. Some herbicides are most effective from late spring to autumn at the start of flowering and before seed set. Other herbicide permits recommend treatment immediately before flowering.

Herbicide options

See Using herbicides for more information.

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PERMIT 89493 Expires 30/09/2026
Amitrole 250 g/L + Ammonium thiocyanate 220 g/L (Various products)
Rate: 1.1 L per 100 L of water
Comments: Spray actively growing plants in riparian areas immediately prior to flowering. Do not broadcast spray over water. See permit for further restrictions and critical comments.
Withholding period: Nil
Herbicide group: 34 (previously group Q), Inhibition of lycopene cyclase
Resistance risk: Moderate

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PERMIT 94283 Expires 31/01/2029
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 grams per 100 L of water plus non-ionic surfactant at a rate of 100 mL per 100 L
Comments: Spray when plants are actively growing from late spring to autumn at commencement of flowering and before seed set. See permit for further restraints and critical comments.
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: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High

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2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 1.0 L per 100 L of water
Comments: Grass pastures only. Spot spray. Apply to young actively growing plants.
Withholding period: Do not graze or cut crops (except sugar cane 8 weeks) or pastures for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Dicamba 750 g/L (Kamba® 750)
Rate: 87 mL per 15 L of water. Add a surfactant.
Comments: Spot spray prior to flowering. For non-crop situations.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Dicamba 750 g/L (Kamba® 750)
Rate: 400 mL per 100 L of water. Add a surfactant.
Comments: Spray prior to flowering. For non crop situations.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Dicamba 750 g/L (Kamba® 750)
Rate: 5.9 L/ha. Use a minimum of 1500 L/ha water carrier. Add a surfactant.
Comments: Boom spray for non-crop situations. Spray prior to flowering.
Withholding period: Do not harvest, graze or cut for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Fluroxypyr 200 g/L (Various products)
Rate: 1.0 L per 100 L of water
Comments: Spot spray during flowering.
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: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Fluroxypyr 333 g/L (Starane™ Advanced)
Rate: 600 mL per 100 L of water
Comments: Spot spray during flowering.
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: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
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 water
Comments: Spray flowering plants with a handgun to the point of run-off. Apply a minimum spray volume of 1250 L/ha.
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: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Tebuthiuron 200 g/kg (Various products)
Rate: 0.5 g /square metre
Comments: Pellet herbicide. Estimate the area within 30 cm beyond the drip zone of each target weed or group of weeds and calculate the amount of needed. Distribute the pellets uniformly within this area. Do not use within 30 m of trees. Do not apply to areas greater than 0.5 ha in size.
Withholding period: Nil.
Herbicide group: 5 (previously group C), Inhibition of photosynthesis at photosystem II - D1 Serine 264 binders (and other nonhistidine binders) (PS II Serine 264 inhibitors)
Resistance risk: Moderate

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Triclopyr 300 g/L + Picloram 100 g/L (Various products)
Rate: 500 mL per 100 L of water
Comments: Spray flowering plants with a handgun to the point of run-off. Apply a minimum spray volume of 1250 L/ha.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the NSW 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.
Central Tablelands	Regional Recommended Measure* (for Regional Priority - Asset Protection) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
Hunter	Regional Recommended Measure* (for Regional Priority - Asset Protection) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
North Coast Exclusion (eradication) zone: Bellingen Shire LGA, Coffs Harbour City LGA, Kempsey Shire LGA, Lord Howe Island, Nambucca Valley LGA, Port Macquarie-Hastings LGA. Core infestation (containment) zone: Ballina Shire LGA, Byron Shire LGA, Clarence Valley LGA, Kyogle Shire LGA, Lismore City LGA, Richmond Valley LGA, Tweed Shire LGA.	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: Land managers should mitigate the risk of the plant being introduced to their land. A person should not buy, sell, move, carry or release the plant into the environment. Exclusion zone: Notify local control authority if found. Land managers should eradicate the plant from the land and keep the land free of the plant. Core infestation: Land managers should mitigate spread of the plant from their land. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
	*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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Disclaimers

Pasture improvement may be associated with an increase in the incidence of certain livestock health disorders. Livestock and production losses from some disorders are possible. Management may need to be modified to minimise risk. Consult your veterinarian or adviser when planning pasture improvement. The Biodiversity Conservation Act 2016 and Local Land Services Amendment Act 2016 restrict some pasture improvement practices where existing pasture contains native species. Contact Local Land Services for further details.

Reviewed 2025