Quick Facts

Quick facts

• Fierce Thornapple (Datura ferox) is a robust, bushy, annual herb that grows to 1 m high and has bright green leaves and white tubular flowers.
• It is found widely in subtropical to temperate areas of Australia and occasionally in tropical and temperate areas.
• The whole plant is toxic to stock and people, with the seeds being the most toxic part.
• It is spread by seeds, often as a contaminant of crop seed, but also in mud on vehicles and by water.
• It is mainly found amongst crops and in other highly disturbed sites such as roadsides and along watercourses.

What Does It Look Like?

What is it?

Fierce Thornapple (Datura ferox) is a much-branched, robust, bushy annual plant that grows to 1 m high, but may flower when only 0.3 m high, rarely less. The leaves are alternately arranged along the stem, stalked, bright green, broadly oval to almost triangular, mostly 80–140 mm long and 50–100 mm wide, rarely 160 mm wide. The leaves have a few short, broadly triangular lobes along each margin, with these lobes also bearing several blunt teeth.

The flowers are borne singly in the branch forks; they are shortly stalked, 40–60 mm long, white, trumpet-shaped, with five short, broad lobes each ending in a narrow tip. There is a tubular, green calyx (outer covering) extending for about half the total flower length from the base; it is angular and 5-toothed.

Fierce Thornapple has capsular, prickly fruits, held erect on the plant. At maturity, the fruit body is egg-shaped, 25–40 mm long and has 40–60 stout, thorn-like prickles, those in the upper half generally markedly longer and mostly 15–25 mm long, sometimes up to 35 mm long. The capsules open up evenly into 4 segments, sometimes only partly so, shedding a large number of seeds. The seeds are D-shaped, pitted, usually black, sometimes grey or grey-brown, 4 to 4.8 mm long. (Haegi 1976; Purdie et al. 1982; Stanley & Ross 1986).

For further information or assistance with the identification of Fierce Thornapple contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Robust, bushy, annual herb

Where it currently grows? Preferred habitat

Fierce Thornapple prefers open disturbed habitats on fertile soils such as cultivated land, alluvial flats and stream banks, but also grows in urban wasteland, on roadsides and in rail reserves. Fertile clayey soils are preferred (Parsons & Cuthbertson 2001; AVH 2021).

Are there similar species?

Fierce Thornapple is somewhat similar to Common Thornapple (Datura stramonium) which also has erect capsules that split evenly into 4 valves, but Common Thornapple has larger flowers, capsules with much smaller and much more numerous prickles and smaller seed (Purdie et al. 1982). It can easily be distinguished from all the other Datura species found in Australia because they all have capsules that are nodding or hang down when ripe and also break open unevenly (Haegi 1976).

Why Is It A Weed?

What are its impacts?

Agriculture: Fierce Thornapple is an important agricultural weed. It is poisonous to stock because of the presence of a number of toxic alkaloids. The seeds are the most poisonous part of the plant. Stock do not generally graze the plants because of their bitter taste and prickly seed pods but are usually affected when they eat contaminated hay, chaff and silage. Fierce Thornapple also competes strongly with many crops (Parsons & Cuthbertson 2001) and may invade native ecosystems, especially along watercourses.

Human impacts: Children are also known to have been seriously poisoned, rarely fatally, after eating parts of the plant (Parsons & Cuthbertson 2001; Smith 1998; WA Department of Primary Industries and Regional Development 2021).

How does it spread?

Fierce Thornapple is dispersed by seed, often as a contaminant of crop seed, when it may be transported thousands of kilometres by road or rail. Seeds are also dispersed by water (because they float), or they may be spread in mud attached to vehicles or machinery (Parsons & Cuthbertson 2001).

What is its history in Australia?

The date of the first naturalization of Fierce Thornapple in Australia is unknown. It was naturalised on the Darling Downs of Queensland by 1916 (Queensland Herbarium 2008) and the North Western Slopes of New South Wales by 1918 (AVH 2021). It is thought to have been accidentally introduced as a contaminant of agricultural seed (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Mechanical control: Mechanical removal of Fierce Thornapple plants is best for small infestations. Large stands on cropping land should be removed by ploughing or tilling the soil. Follow-up will be needed to remove seedlings that germinate in subsequent seasons.

Chemical control: Small plants are susceptible to herbicide, but this treatment may be ineffective for mature plants (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)

Fierce Thornapple is an annual plant with growth rates of up to 2 cm per day. It germinates predominantly in spring and summer from depths of up to 7 to 8 cm in temperatures of 20 to 35°C. but seeds may germinate at any time of the year given at least 10 mm of rainfall or irrigation. Cultivation appears to stimulate germination by exposing the seeds to light. Flowers may be produced when the plant is only 2-5 weeks old. It flowers and fruits throughout the summer and autumn, but is generally killed by frosts in early winter. The seeds may remain dormant for long periods and have been known to germinate after 20 years (Parsons & Cuthbertson 2001; Smith 1998; Cotton Catchment Communities CRC 2007).

Where Is It Found?

Which states and territories is it found?

NSW, NT, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Fierce Thornapple is naturalised in south-western Western Australia; widely though very scattered in subtropical and arid Northern Territory;  temperate and semi-arid South Australia; mainly along the Murray River in central northern Victoria; sporadically at a range of sites in settled parts of Tasmania; mainly on the western slopes and western plains regions west of the Great Dividing Range in New South Wales; and widely in central and southern Queensland (Purdie et al. 1982; Parsons & Cuthbertson 2001, AVH 2021).

Where does it originate?

The origin of Fierce Thornapple and all Datura species is in Central America (principally Mexico) and the southern USA (Symon & Haegi 1999).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NT, TAS, 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

Datura ferox

Other scientific names (synonyms)?

Datura quercifolia Kunth

Does it have other known common name(s)?

Longspine Thornapple