Harrisia cactus (Harrisia species)

Also known as: Harrisia

Harrisia cacti are low-growing, spiny cacti with white flowers and red fruit. They have sharp spines that can seriously injure people and animals.

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How does this weed affect you?

Harrisia cacti are difficult to control as they produce thousands of viable seeds and have fleshy storage tubers. They form impenetrable thickets which:

• out compete grasses and reduce productivity of grazing land
• prevent movement of livestock
• make mustering difficult
• restrict access to watering points
• provide habitat for feral animals such as rabbits
• compete with native plants especially in acacia-wooded grasslands. 

The sharp spines on harrisia cacti can:

• cause painful injuries to people, livestock, working dogs and pets
• injure and sometimes kill wildlife that get trapped in the spines
• devalue wool and hides and prevent shearing.

What does it look like?

Harrisia cacti form dense tangled mats up to 0.6 m high. The stems can also climb up other plants to a height of 2-3 m.

There are three species of Harrisia in NSW:

• H. martinii
• H. tortuosa
• H. pomanensis

Stems (also called pads or cladodes) are:

• green
• fleshy and spiny 
• slender and branched, often tangled
• jointed every 30-45 cm
• 2-5 cm in diameter (H. tortuosa usually up to 5 cm and H. martini up to 4 cm).

H. martini has 4-5 ridges and prominent pyramid shaped humps along the stem.

H. tortuosa has 6-8 ridges and only slight humps along the stem.

H. pomanensis has slight humps on the stem ridges.

Stem spines

Areoles are rounded areas on the humps along the stem. Each areole produces a group of spines.

H. martini spines consist of:

• a central spine 2-3.5 cm long
• surrounded by 1-3 spines 1.0-1.5 cm long
• and a row of spines 3-6 mm long.

H. tortuosa spines consist of:

• a central spine 3-5 cm long
• surrounded by 4-8 spines 1–3 cm long.

H. pomanensis spines consist of:

• 1-3 larger spines 1-2 cm long
• 6-8 spines up to 1 cm long held close to the stem. 

 Flowers are:

• white, tinged with pink
• funnel shaped with a green base
• up to 20 cm long
• open at night and whither in the morning.

Fruit are:

• red with white flesh and black seeds
• round
• 2-4 cm in diameter.

H. martini fruit are warty with spines up to 5 mm long.

H. tortuosa fruit do not have warts and usually have a few spines.

H. pomanensis fruit do not have spines.

Roots

There are two types of roots:

• fibrous shallow roots up to 10 cm deep
• fleshy storage tubers up to 50 cm deep.

Where is it found?

H. martini is most common in the North West region of NSW from the Queensland border to Moree. It is also found in the Central West, Western Region, Central Tablelands and Riverina. 

H. tortuosa has been found in the North West, Central West and Upper Hunter in NSW.

H. pomanensis is the least common species in NSW. Plants have been found around Grawin (near Lightning Ridge) and Leichardt.

Harrisia cacti are from South America. 

What type of environment does it grow in?

Harrisia cacti grow in semi-arid scrublands with summer rainfall. They prefer fertile clay soils and are common in acacia-wooded grasslands such as the brigalow forests.

Maps and records

• Recorded presence of Harrisia cactus during property inspections (Map: Biosecurity Information System - Weeds, 2017-2022)
  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.
  
  
• Estimated distribution of Harrisia cactus in NSW (Map: NSW Noxious Weed Local Control Authorities, 2010)
  Map shows weed distribution and density estimated by local council weeds officers in 2010.

How does it spread?

Harrisia cacti were originally introduced to Australia as ornamental plants.

By seeds

The plant can begin to produce seed by six months of age and from then on can continue to produce fruit almost all year round. Each fruit produces 400 – 1000 seeds. Birds eat the fleshy fruit and spread the seeds in their droppings. 

By plant parts

Plants can regrow from stems fragments and root tubers. Wild pigs can spread the tubers. The stems can spread by sticking to animals, people, vehicles and machinery.

References

DAF (2020). Queensland Government Department of Agriculture and Fisheries Restricted Invasive Plants: Harrisia cactus. Retrieved 12 August 2020 from: https://www.daf.qld.gov.au/plants/weeds-pest-animals-ants/weeds/a-z-listing-of-weeds/photo-guide-to-weeds/harrisia-cactus?a=49179

Identic Pty Ltd. and Lucid central  (2016). Environmental Weeds of Australia Fact sheet: Harrisia. Retrieved 12 August 2020 from: https://keyserver.lucidcentral.org/weeds/data/media/Html/harrisia_martinii.htm

Kleinschmidt, H. E., Johnson, R. W., & Everist, S. L. (1977). Weeds of Queensland. SR Hampson, Govt. printer.

Lamp, C. & Collet, F. (1989). Field guide to weeds in Australia (No. Ed. 3). Inkata Press.

McFadyen, R. (2012). Harrisia (Eriocereus) martinii (Labour.) Britton – Harrisia cactus Acanthocereus tetragonus (L.) Hummelink – sword pear In Cullen, J., Julien, M., & McFadyen, R. (Ed.), Biological control of weeds in Australia. (pp. 274 – 281). CSIRO Publishing.

Parsons, W.T. & Cuthbertson, E.G. (2001). Noxious Weeds of Australia, CSIRO Publishing, Collingwood.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 12 August 2020 from: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Harrisia

More information

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Control

When controlling harrisia cacti wear protective clothing, including gloves, boots, thick clothing and eyewear to stop injuries from spines.

Biological control

A mealybug (Hypogeococcus festerianus) has provided a significant level of control in the central Queensland part of the invaded range, however, in southern Queensland and adjacent New South Wales (where temperatures are cooler) the mealybug develops more slowly, especially in the shade. As a result, control is slow and alternative biological control solutions are required.

Physical removal

Use tools to remove plants and ensure all of the tubers are dug out. Take care to dispose the whole plant and check for any parts that have fallen off. 

Disposal 

To dispose cacti bury them at 1 m deep or burn in a hot fire. Check disposal sites regularly. Alternatively contact your local council for disposal advice.

Spraying

Apply herbicide to actively growing plants. Ensure all parts of the plant are treated. Re-treatment may be necessary, particularly with large clumps of cacti. 

Herbicide options

See Using herbicides for more information.

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PERMIT 80069 Expires 30/09/2023
Triclopyr 200 g/L + Picloram 100 g/L with Metsulfuron-methyl 600 g/kg (Various products)
Rate: 150 - 350 ml plus 20 grams in 100 L of water
Comments: Apply to actively growing plants
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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PERMIT 14442 Expires 30/06/2023
Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon Extra®)
Rate: 500 mL in 100 L water
Comments: Apply as a thorough foliar spray.
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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PERMIT 14442 Expires 30/06/2023
Triclopyr 300 g/L + Picloram 100 g/L (Various products)
Rate: 500 mL per 100 L water
Comments: Apply when there is active phyllode (leaf) growth.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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PERMIT 14442 Expires 30/06/2023
Triclopyr 600 g/L (Garlon® 600)
Rate: 1.0 L per 75 L of distillate
Comments: Apply as a thorough foliar spray.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Dichlorprop 600 g/L (Lantana 600®)
Rate: 1.0 L per 60 L of water
Comments: Good soil moisture essential and spray at fruiting.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Triclopyr 240 g/L + Picloram 120 g/L (Access™ )
Rate: 1.0 L per 60 L of diesel
Comments: Foliar application.
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 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 - Prevention) Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. This Regional Recommended Measure does not apply to cultivated plants.
Central West	Regional Recommended Measure* (for Regional Priority - Eradication) Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment.
North West An exclusion zone is established for all lands in the region, except the core infestation area, comprising the Gwydir Shire council and Moree Plains Shire council	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: The plant should not be bought, sold, grown, carried or released into the environment. Exclusion zone: Land managers should mitigate the risk of new weeds being introduced to their land; the plant should be eradicated from the land and the land kept free of the plant. Core infestation: Land managers reduce impacts from the plant on priority assets This Regional Recommended Measure applies to Harrisia martinii and Harrisia tortuosa
Northern Tablelands	Regional Recommended Measure* (for Regional Priority - Asset Protection) Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. The plant should not be bought, sold, grown, carried or released into the environment. This Regional Recommended Measure applies to Harrisia martinii and Harrisia tortuosa
Western	Regional Recommended Measure* (for Regional Priority - Asset Protection) Land managers should mitigate spread from their land. Land managers reduce impact of plant on priority assets (grazing conservation and urban areas). The plant should not be bought, sold, grown, carried or released into the environment. This Regional Recommended Measure applies to Harrisia martinii
	*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 2021