Datura metel (Angel's Trumpet)

Scientific name

Datura metelL.

Synonyms

Datura metel var. dentata Schltdl. & Cham.; Datura metel var. fastuosa (L.) Saff.; Datura metel var. flaviflora (O.E.Schulz) Moldenke; Datura metel var. muricata (Link) Danert; Datura metel f. pleniflora O.Deg.; Datura metel var. quinquecuspidataTorr.

Common names

Angel's trumpet, cornucopia, datura, devil's trumpet, downy thorn-apple, Hindu datura, Hindu thorn-apple, hoary thorn-apple, horn-of-plenty, jimson weed, metel, purple thorn-apple, thorn apple

Family

Solanaceae

Origin

The origin of Datura metel is unclear.

Naturalised distribution (global)

Locations within which Datura metel is naturalised include India, east African and some oceanic islands with warm climates.

Introduced, naturalised or invasive in East Africa

Datura metel is invasive in parts of Kenya, Tanzania and Uganda. In Kenya D. metel has been recorded in the Aberdares, Kisii and the Taita Hills. It occurs in altitudes ranging from 50-2200m above sea level and is more common at the coast. It is widespread in Tanzania.

Habitat

Cultivated in gardens, farmlands around the world but also a frequent garden escape.

Description

Datura metel is a shrub to 1.4 m tall and somewhat variable in appearance. Its stems are slightly furry, with dark violet young shoots.

D. metel has almost hairless leaves, oval to broad oval, smooth and are often dark violet in colour. Also, leaves are less sharply toothed or more or less entire.

D. metel flowers are immensely varied, and can be single or double. Flower colour ranges from white to cream, yellow, red, and violet. They are pleasantly scented particularly in the night.

The fruits are knobby, not spiny with blunt protuberances, or with longer prickles.

Reproduction and dispersal

Datura metel reproduces through seed.

Similar species

Datura ferox and Datura stramonium (common thornapple) produce erect capsules on straight stalks which contain black or grey seeds.

Datura leichhardtii, Datura metel, Datura inoxia and Datura wrightii can be differentiated from these two species as their capsules are held on a curved stalk, and they produce brown or yellow seeds.

D. ferox can be distinguished from D. stramonium by its capsule which, has about 40-60 spines of variable length.

D. ferox flower is shorter (4-6 cm long) compared to the flower of D. stramonium which is longer, up to 10 cm long.

Brugmansia species may be confused with Datura species. Brugmansias long-lived (perennial) while daturas are annual. Both plants have a trumpet shaped flower; but those of brugmansias point downwards while datura's flowers most often point upward. Brugmansias emit a sweet fragrance while datura's fragrance can be described as spicy or lemony.

Economic and other uses

Datura metel can be grown as an ornamental plant. However, this use cannot compensate for this plant's overall negative impacts.

Environmental and other impacts

Datura metel may be toxic if ingested even in small quantity. Symptoms associated with D. metel poisoning include flushed skin, headaches, hallucinations, and possibly convulsions or even a coma. All parts of Datura plants contain dangerous levels of poison and may be fatal if ingested by humans and other animals, including livestock and pets. D. metel has been listed as a noxious weed in several Australian states. In some countries of the world, it is also prohibited to buy, sell or cultivate Datura plants.

Management

The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species. Some components of an integrated management approach are introduced below.

The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.

Datura metal can be managed by digging it up or otherwise removing it. It can also be sprayed with a suitable herbicide. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

The editors could find no information on any biological control agents for this species.

Legislation

This species has been declared a noxious weed under the Noxious Weeds Act CAP 325, in Kenya. Accordingly the Minister of Agriculture, can compel land owners who have such declared noxious weeds growing on their land to eradicate or have it otherwise removed.

References

Government of Kenya (1983). The Suppression of Noxious Weeds Act: CAP 325 of the Laws of Kenya. 2nd Ed. Government Printer, Nairobi, 5 pp.

Henderson, L. (2001).  Alien weeds and invasive plants. A complete guide to declared weeds and invaders in South Africa.  Plant Protection Research Institute Handbook No. 12, 300pp. PPR, ARC South Africa.

Editors

Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.

Acknowledgments

This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke