Quick Facts

Quick facts

• Originally from southern North America, Purpleflower Devil's Claw (Proboscidea louisianica) is an annual invasive species inhabiting tropical, sub-tropical and warm temperate, and arid to semi-arid areas in New South Wales,  South Australia, Western Australia, and Queensland.
• It is mainly an agricultural weed, and is found on roadsides, river flats, sandy soil, and cultivated areas, but it occurs as isolated plants or small clusters, and rarely forms large colonies.
• The fruit have large woody claws that can attach to livestock, clothing, machinery or vehicles, which is a major form of dispersal.
• These claws can cause injury or death to animals.
• It can compete strongly with summer crops such as cotton.
• It is most readily controlled by manual removal, as it does not resprout from its roots.
• Chemical control can be used while actively growing before fruiting stage.

What Does It Look Like?

What is it?

Purpleflower Devil's Claw (Proboscidea louisianica) is a low growing, erect sticky annual herb growing 20–50 cm high. Stems are stout, branched and hollow, and covered with glandular hairs that secrete a slimy, sticky sap. Large  rounded leaves with a heart shaped base, 6–16 cm long, 5–14, cm across, leaf tip (apex) rounded to sharply pointed,. The leaf margins are  entire (smooth with no teeth or lobes) to shallowly sinuate (with wave-like depressions along the margins). Leaves arranged in opposite pairs along the stem, and are covered with hairs similar to those on the stems. Petioles (leaf-stalks) are approximately 5–20 cm long.

The relatively large showy flowers, are in branched loose clusters on a main axis 9–20 cm long with few to 10 or more flowers per flower cluster. Individual showy trumpets flowers are 2.5–5 cm long and 5–7.5 cm wide, borne on stalks are 2.5–3.5 cm long. Flowers are cream, or white to purple and have dark orange and purple markings (dots and lines) in the throat.

The fruit is 8–30 cm long in total, consisting of a larger bulbous capsule 5–9 cm long at the attached end, and two curved claws or horns 10–17 cm long, splitting from the body of the bulbous capsule, with claws curving back on itself 180 degrees. The fruit is brown or black with a rough surface, becoming hard and woody as it matures with the bulbous capsule containing numerous seeds. The seeds are black or grey, strongly wrinkled, variable in shape, and approximately 10 mm long and 6 mm wide (Parsons 1973; Parsons & Cuthbertson 2001; Richardson et al. 2006; VicFlora 2016).

For further information and assistance with identification of Purpleflower Devil's Claw contact the herbarium in your state or territory.

Flower colour

Cream, White, Purple

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Purpleflower Devil's Claw occurs in tropical, subtropical and temperate regions, and arid to semi arid areas, predominantly on highly fertile soils to poor sandy soils. In Australia, it is generally found on disturbed sites such as roadsides, river flats and cultivated areas (Parsons & Cuthbertson 2001). It establishes best in open spaces, but has been recorded growing in shaded areas (Agriculture Victoria 2021).

Are there similar species?

Yellowflower Devil's Claw (Ibicella lutea) is very similar to Purpleflower Devil's Claw, but can be distinguished by its yellow flowers, with red or purple markings, that are relatively densely clustered. Also, Yellowflower Devil's Claw has fruits 10–25 cm long, light brown, with short spines at the base, while the fruits in Purpleflower Devil's Claw are 8–30 cm long, brown or black, with a rough or pitted surface (Navie 2004; Parsons & Cuthbertson 2001; Richardson et al. 2006).

Devil's Claw (Martynia annua), is also similar but has pink to lavender flowers, and smaller fruits (3–4 cm long), with very short claws that are shorter than the fruit (Navie 2004; Parsons & Cuthbertson 2001; Richardson et al. 2006).

Why Is It A Weed?

What are its impacts?

Native ecosystems: Purpleflower Devil's Claw is not known to have any major impact on native flora and fauna as it occurs singly or in small patches, rarely forming large colonies, and most often only occurs on disturbed land. It is only documented as occurring in semi arid to arid natural ecosystems. However, as it is a low growing herb, it may have potential to displace other herbs, forbs or grasses (Agriculture Victoria 2021).

Agriculture: A weed of pastures in drier areas. While stock do not graze this plant due to the sticky discharge, serious injury can occur to animals if the hard, clawed (horned) fruit are caught in the mouth or nose. The fruit can also cause damage when the claws work into the animal's body or feet (Robbins et al. 1970; Parson 1973; Lamp & Collet 1976; Parsons & Cuthbertson 2001), or lodge around the animals mouth preventing feeding and animals can stave to death. However its preferred habitat it river flats and horticultural crops. This species can compete strongly with summer and horticultural crops such as cotton, and it is particularly drought tolerant due to its extensive root system (Agriculture Victoria 2021; Parsons 1973), with the woody fruits interfering with harvesting causing damage to machinery. Purpleflower Devil's Claw is also grown for its fruit, which are collected when young, and then pickled (Robbins et al. 1970; Parsons & Cuthbertson 2001).

How does it spread?

The claws of the fruits of Purpleflower Devil's Claw attach readily to passing animals, dispersing the seeds. Sheep are considered to be a particularly important method of dispersal. Seed transport is the only known dispersal mechanism of this species, and plants are able to produce up to 8000 seeds per plant (Agriculture Victoria 2021). Seeds are eaten by cockatoos, but it is unknown whether or not this results in seed dispersal (Parsons 1973; Parsons & Cuthbertson 2001). Experiments suggest that cross pollination is necessary for seed development (Agriculture Victoria 2021).

What is its history in Australia?

The precise time of introduction of Purpleflower Devil's Claw into Australia is not known, but it was probably introduced as an ornamental, or possibly accidentally, attached to bags or merchandise (Parsons 1973). This species was recorded in the Adelaide Botanic Gardens in 1858, and was considered naturalised in Victoria by 1882 (Parsons & Cuthbertson 2001). However, the first herbarium records with dates are: Queensland in 1891; Victoria in 1882; NSW in 1905; South Australia in 1912;  Western Australia 1971; ACT 1978 (AVH 2021).

How To Manage It?

Best practice management

Non-chemical control: Purpleflower Devil's Claw is not difficult to manage and can be effectively removed by cultivation or hoeing up until flowering. This species is only known to reproduce by seeds and will not resprout from the roots. If flowering does occur, plants should be destroyed properly by burning (Parsons 1973; Parsons & Cuthbertson 2001).

Chemical control: Herbicides should be applied to actively growing seedlings or adult plants up until flowering, see: (DPI NSW 2019; DPIRD WA 2021; Ensbey & Johnson 2007; Parsons & Cuthbertson 2001).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Flowering and fruiting occurs mostly from February to March. Seeds germinate in spring, and the plant grows rapidly through spring and summer, dying off in autumn as temperatures drop (Parsons 1973, Parsons & Cuthbertson 2001, eFlora of SA 2007).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, VIC, WA

What areas within states and territories is it found?

Purpleflower Devil's Claw occurs in all mainland states, with the exception of the Northern Territory. It occurs as isolated plants or in small patches, and rarely forms large colonies (Parsons & Cuthbertson 2001). 

This species is most problematic in New South Wales in sub-coastal regions (Navie 2004).

 In Victoria it occurs most commonly in the north along the Murray River, and also in the Werribee district (Parsons 1973), however, it is now only reported to be formally naturalised and not present in Victoria (APC 2021) . 

In Western Australia it has been recorded near Perth, Kalgoorlie and Carnarvon (Hussey et al. 2007). 

In Queensland, it is recorded mainly from central and sub-coastal areas (Kleinshmidt & Johnson 1977). 

In South Australia it is recorded from the Flinders Ranges in arid to semi arid environments, to higher rainfall areas furthers south across the northern and southern Lofty Ranges, and Murray regions (AVH 2021; Barker 1986).

Seasonal variation in the density of devil's claw infestation is evident, with many more plants present in some years than others (Parsons & Cuthbertson 2001), most likely attributed to rainfall events.

Where does it originate?

Purpleflower Devil's Claw is native to southern North America (Mississippi Valley, Sacramento Valley, southern California), where it is now widely distributed, and can be found in sandy soils, cultivated fields, waste areas, and stream banks (Uvalde Research and Extension Centre 2000). In North America, it can occur densely in grazing lands and is becoming an important agricultural weed (Parsons & Cuthbertson 2001). It is a declared noxious weed in Washington (USDA 2007).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

VIC, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Proboscidea louisianica

Other scientific names (synonyms)?

• Martynia fragrans Lindl.
• Martynia louisiana Mill.
• Martynia louisianica B.D.Jacks (incorrect spelling)
• Martynia proboscidea Gloxin
• Proboscidea fragrans (Lindl.) Decne.
• Proboscidea jussieui A.Keller
• Proboscidea louiseana Wooton & Standl. (incorrect spelling)
• Proboscidea louisiana subsp. fragrans (Lindl.) Bretting
• Proboscidea louisiana (Mill.) Thell. subsp. louisiana
• Proboscidea louisianica Thell. (incorrect spelling)
• Proboscidea louisianica subsp. fragrans Bretting (incorrect spelling)
• Proboscidea louisianica Thell. subsp. louisianica (incorrect spelling)

Does it have other known common name(s)?

Purple-flowered Devil's Claw, Elephant Tusks, Goat Head, Common Devil's Claw, Ram's Horn, Unicorn Plant, Proboscis Flower, Louisiana Unicorn-Plant