Click on images to enlarge
cluster of open and unopen buds (Photo: Emily Wabuyele)
close-up of flowers (Photo: Sheldon Navie)
young plant (Photo: Sheldon Navie)
early roadside infestation (Photo: George Mugambi)
advanced infestation of roadside (Photo: George Mugambi)
Side view of upper leaves and buds (Photo: Emily Wabuyele)
habit of younger tree (Photo: Sheldon Navie)
immature and mature fruit (Photo: Sheldon Navie)
flower buds (Photo: Sheldon Navie)
close-up of leaf underside (Photo: Sheldon Navie)
upper leaves and flower clusters (Photo: Sheldon Navie)
habit of mature tree (Photo: Forest and Kim Starr, USGS)
young leaves (Photo: Sheldon Navie)
younger stem and lower leaves (Photo: Sheldon Navie)
seedling (Photo: Sheldon Navie)
close-up of seeds (Photo: Steve Hurst at USDA PLANTS Database)
Nicotiana glauca var. angustifolia Comes; Nicotiana glauca var. decurrens Comes; Nicotiana glauca var. grandifloraComes
Native to South America.
Nicotiana glauca is present in Kenya, Tanzania and Uganda. It is invasive in parts of Kenya (A.B.R. Witt pers. obs.) and Tanzania (Henderson 2002).
Nicotiana glauca grows in a wide variety of open and disturbed habitats including roadsides and lakeshores. It is mainly a problem in relatively dry areas.
Its leaves are thick and rubbery up to 20 cm long. It has yellow tubular flowers about 5 cm long and 1 cm wide.
This plant reproduces by seed.
Nicotiana glauca is an ornamental plant. It has insecticidal properties. However, these uses cannot compensate for this plant's overall negative impacts.
Nicotiana glauca poses a threat to biodiversity by competing with native species for resources and displacing native plants. All parts of the plant are poisonous. N. glauca has been included in the Global Invasive Species Database (GISD 2010). It has been listed as a noxious weed in South Africa (prohibited plants that must be controlled. They serve no economic purpose and possess characteristics that are harmful to humans, animals or the environment).
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.
Seedlings and young plants can be pulled or dug out. Larger plants can be cut and the stumps treated with herbicide. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.
Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.
Cronk, Q.C.B. and Fuller, J.L. (1995). Plant Invaders. Chapman and Hall, London.
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.
Pacific Island Ecosystems at Risk (PIER). Nicotiana glauca R.C.Graham, Solanaceae: plant threats to Pacific ecosystems. www.hear.org/pier/species/nicotiana_glauca.htm. Institute of Pacific Islands Forestry, Hawaii, USA.
Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.
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).
BioNET-EAFRINET Regional Coordinator: [email protected]