Catharanthus roseus (Madagascar Periwinkle)

Scientific name

Catharanthus roseus (L.) G. Don.

Synonyms

Ammocallis rosea (L.) Small; Lochnera rosea (L.) Reichb.; Vinca roseaL.

Common names

Madagascar periwinkle, rosy periwinkle, bright-eyes, Cape periwinkle, old-maid, periwinkle, pink periwinkle, rose periwinkle, vinca.

Family

Apocynaceae

Origin

Catharanthus roseus is native and endemic to Madagascar.

Naturalised distribution (global)

Catharanthus roseus has been naturalised in practically all tropical countries.

Introduced, naturalised or invasive in East Africa

Catharanthus roseus is invasive in parts of Kenya and naturalised in parts of Uganda (A.B.R. Witt pers. obs.) and Tanzania (Henderson 2002). C. roseus is cultivated as an ornamental in most districts of Tanzania, including Iringa, Marangu, Mwanza, Ukiriguru, Amani, Dar es Salam; In Uganda, it is cultivated in Mengo, Karamoja; it is widespread in Kenya-Nairobi, Kiambu, Embu, Kisii, Taita Taveta, Kakamega.

Habitat

Rocky outcrops and roadsides in dry savanna, urban open spaces and in cultivated areas.

Description

Catharanthus roseus is a long-lived (perennial) sub-shrub or herb, usually erect, 30-100 cm high and at least somewhat woody at the base, sometimes sprawling. White latex is present.

Stems cylindrical (terete), longitudinally ridged or narrowly winged, green or dark red, pubescent at least when young. Leaves opposite, borne on short petioles, 2.5-9.0 cm long, usually elliptical to obovate (egg-shaped in outline but with the narrower end at the base), green with paler veins . The leaf tip is rounded to acute with a tiny point extending from the midrib. Stems and leaves usually with hairs (pubescent), sometimes hairless.

Flowers borne in leaf axils, either singly or paired on very short stalks (pedicels). Sepals 5, 2-6 mm long, narrow, usually with hairs (pubescent). Corolla with a long narrow tube and lobes that spread perpendicular to the tube and almost flat.; corolla tube greenish, usually at least 2.2 cm long, with the inside of the mouth often dark pink or sometimes yellow, pubescent inside the throat with rings of stiff hairs below the mouth and anthers; corolla lobes 5, pink to white or pinkish purple, 1.0-2.8 cm long, obovate. Anthers 5, attached to the inside of the corolla tube in the upper portion and concealed within it.

The fruit is a follicle, 2.0-4.7 cm long, with numerous small black seeds.

Reproduction and dispersal

Flowers of Catharanthus roseus are pollinated by  butterflies and moths. This species is self-compatible, though self-pollination under normal conditions may be relatively uncommon.  Seeds are dispersed by ants, wind and water.

Economic and other uses

Catharanthus roseus has anti-cancer effects and is traditionally used to treat diabetes, It is a popular ornamental plant in East Africa.

Environmental and other impacts

Catharanthus roseus is most commonly associated with coastal habitats (e.g. cliff faces, rocky ocean ledges and sand dunes) and other sites with sandy soils, but also grows in bushland and disturbed natural vegetation near urban areas. It is a common garden plant in East Africa; it frequently escapes to inhabit roadsides, abandoned quarries and farmland.

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

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.

Henderson, L. (2002). Problem plants in Ngorongoro Conservation Area. Final Report to the NCAA.

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