Quick Facts

Quick facts

  • Leichhardt's Thornapple (Datura leichhardtii) is a robust, bushy, annual herb that grows to 1.2 m high and has bright green leaves and white tubular flowers.
  • It is found widely in arid, semi-arid and subtropical areas of Australia, especially along watercourses or in open grassland on heavier soils.
  • It is toxic to stock and people.
  • It is spread is by seeds along watercourses  and in floodwater; possibly also spread when the prickly light fruit adheres to animal fur.
  • It is mainly found on disturbed sites such as in dry watercourses, along creek banks, alluvial flats and on roadsides.

What Does It Look Like?

What is it?

Leichhardt's Thornapple (Datura leichhardtii) is a much-branched, robust, bushy, annual plant that grows to 1.2 m high but may flower when only 0.1 m high. The branches are green.  The leaves are alternately arranged along the stem, stalked, bright green, broadly trowel-shaped to oval, mostly 50-70 mm long (sometimes up to 80 mm) and 20-45 mm wide. The leaves have several short, broadly triangular, angular or rounded lobes along each margin, all of similar size. 

The flowers are borne singly in the branch forks; they are shortly staked, 45-70 mm long, white, cream or faintly rose-tinged towards the top, with 5 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 rounded and 5-toothed. 

Leichhardt's Thornapple has capsular, prickly fruits, that bend downwards. At maturity, the fruit-body is globular, sometimes broadly egg-shaped, 20-25 mm long and has very numerous slender prickles of uneven length all distributed evenly, the longer ones 4-9 mm long. The capsules break up unevenly or may partly open up evenly into 2 or 4 segments initially, usually then further breaking unevenly, shedding a large number of seeds. The seeds are more or less ear-shaped, markedly narrowed towards the base, finely pitted, light brown to grey-brown, 4-4.8 mm long ( Haegi 1976; Purdie et al. 1982).

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

Flower colour

White or white with rose tinting

Growth form (weed type/habit)

Much-branched, robust, bushy, annual herb.

Where it currently grows? Preferred habitat

Leichhardt's Thornapple is naturalised in parts of semi-arid, arid and subtropical Australia. It prefers open disturbed habitats such as dry watercourses, stream banks and floodplains and roadsides where there is run-off, but sometimes (especially in Queensland) grows in open grassland on heavy clay soils (Haegi 1976). 

Are there similar species?

Leichhardt's Thornapple can be distinguished from all other Thornapples except Fierce Thornapple (D. ferox) by its short flower which is only 40 to 70 mm long. Fierce Thornapple has flowers of a similar size but it has an angular calyx (lower outer covering), its fruit are held erect on the plant, and have only 40 – 60 stout prickles per fruit, the longer ones 15 – 25 mm long; in contrast, Leichhardt's Thornapple, has a smooth, rounded calyx, and capsules with numerous fine prickles, the longer ones only 4 – 9 mm long. (Haegi 1976; Purdie et al. 1982).

Why Is It A Weed?

What are its impacts?

Agriculture: Leichhardt's Thornapple is principally a weed of pastoral areas, especially as an invasive weed of native vegetation. Although it is toxic to stock because of the presence of a number of toxic alkaloids in the foliage and seeds, information on stock poisoning by this species is scarce.

Human impacts: There are some early references to poisoning of children from eating seeds of this species in remote parts of South Australia  (Symon & Haegi 1991).

How does it spread?

Leichhardt's Thornapple is dispersed by seed in water when intermittent watercourses flow and in floodwater across low-lying areas floodplains. It may also be spread when the light, seed-containing prickly capsules are caught on animal fur. Along roadways and tracks the seed may be spread in mud adhering to vehicles or machinery.

What is its history in Australia?

In spite of its central American origin, Leichhardt's Thornapple was first described from Australia, leading to the general view that it was a native species. More recently it became apparent that it was the same as a species (Datura pruinosa) described subsequently from Mexico. It has been concluded that Leichhardt's Thornapple is very likely an early, possibly pre-European, human-mediated introduction to Australia but the details remain unknown (Haegi 1976; Symon & Haegi 1991). It is still considered a native species by some botanists.

How To Manage It?

Best practice management

Non-chemical control: Mechanical control: Mechanical removal of Leichhardt's Thornapple plants is effective for small infestations.

Chemical control: Small plants of all thornapple species 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?


When does it grow? (lifecycle/growth calendar)

Leichhardt's Thornapple is a robust, bushy annual herb. 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 (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?


What areas within states and territories is it found?

Leichhardt's Thornapple is found in the Pilbara and Gascoyne regions of mid-northern Western Australia; principally in southern arid parts of Northern Territory; in semi-arid and arid South Australia; only from a few sites around and to the north of Broken Hill in far western New South Wales (near the SA border) and widely in subtropical and arid Queensland, north of 27o S Latitude (Haegi 1976; Purdie et al. 1982; Parsons & Cuthbertson 2001; AVH 2021).

Where does it originate?

The origin of Leichhardt's Thornapple is Mexico and Guatemala (Haegi 1976; Symon & Haegi 1999).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?


Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?


Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?


Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Datura leichhardtii

Other scientific names (synonyms)?

Datura pruinosa Greenm.

Datura leichhardtii subsp. pruinosa (Greenm.) A.S. Barclay ex K Hammer


Does it have other known common name(s)?

Mexican Thornapple, Native Thornapple

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