Mirabilis jalapa (Four o'clock)

Scientific name

Mirabilis jalapaL.

Synonyms

Jalapa officinalis Garsault; Nyctago jalapae (L.) DC.; Nyctago versicolor Salisb.; Mimosa hispidula Kunth  

Common names

Four o'clock, beauty of the night, beauty-of-the-night, coat of many colours, false jalap, four o'clock, four o'clock flower, four o'clock plant, four-o'clock, garden four-o'clock, marvel of Peru, marvel-of-Peru

Family

Nyctaginaceae

Origin

The exact origin of Mirabilis jalapa is obscure, but it is thought to be native to parts of tropical America.

Naturalised distribution (global)

Locations within which Mirabilis jalapa is naturalised include the warmer parts of Australia, USA and New Zealand and many Pacific islands.

Introduced, naturalised or invasive in East Africa

Mirabilis jalapa is naturalised in parts of Tanzania and invasive in Kenya and Uganda (A.B.R. Witt pers. obs.). In Kenya, M. jalapa is cultivated in areas around Nairobi and Naivasha; in Uganda in the Ankole and Mengo districts and in the Mabira Forest; and in Tanzania in the Rubondo, Lushoto and Mpwapwa districts.

Habitat

Mirabilis jalapa is cultivated in gardens and has also been recorded on waste ground and around habitation areas. It occurs altitudes ranging from 200-2150 m above sea level.

Description

Mirabilis jalapa is a long-lived (perennialherb growing up to 2 metres high, with a tuberous root.

Its leaves are egg-shaped in outline with broad end at base (ovate), oblong, or triangular, measuring to 9 cm long.; the leaf tip is acute, base cordate. The leaf stalk (petiole) is 4 cm long.

Flowers of M. jalapa occur in groups of  3-7; flower stalks more or less absent; flowers are fragrant and open in the afternoon; flowers are tubular, white, pink or red in colour, up to 6.5 long  by 3.5 wide with 5-6 stamens.

The fruit is a small, one-seeded capsule (anthocarp).

Reproduction and dispersal

Self-pollination has been was described  the primary means of reproduction in Mirabilis jalapa and in some natural populations hawk-moth pollinators have been reported. M. jalapa spreads by seed.

Economic and other uses

Mirabilis jalapa is cultivated in gardens for ornamental purposes. It is also said to be medicinal, with antivirus properties.

Environmental and other impacts

Mirabilis jalapa is regarded as a minor environmental weed or "sleeper weed" in many parts of  the world where it has spread been introduced. It escape from gardens to crop fields and other disturbed areas, is capable of withstanding extended droughts due to the tuberous roots. It has potential to outcompete indigenous vegetation. The seeds and plant are poisonous if ingested.

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.

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.

The editors could not find any specific information on the management of this species.

Legislation

Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.

References

Pacific Island Ecosystems at Risk (PIER). Mirabilis jalapa L., Nyctaginaceae: plant threats to Pacific ecosystems. www.hear.org/pier/species/mirabilis_jalapa.htm. Institute of Pacific Islands Forestry, Hawaii, USA. Accessed March 2011.

Whitehouse C. (1996). Nyctaginaceae. In Polhill  R.M. (ed.). Flora of Tropical East Africa. AA Balkema, Rotterdam.

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