Cirsium vulgare (Spear Thistle)

Scientific name

Cirsium vulgare (Savi) Ten.

Synonyms

Carduus lanceolatus L.; Carduus vulgarisSavi

Common names

Spear thistle, bank thistle, bird thistle, black thistle, blue thistle, boar thistle, bull thistle, bur thistle, button thistle, common bull thistle, common thistle, Fuller's thistle, green thistle, plume thistle, roadside thistle, Scotch thistle, swamp thistle.

Family

Asteraceae (Compositae)

Origin

Cirsium vulgare is native to Europe, northern Africa, western Asia, Pakistan and China.

Naturalised distribution (global)

Locations within which Cirsium vulgare is naturalised include Africa and Asia, New Zealand, Australia, USA, Canada, South America, Hawaii and other Pacific islands.

Introduced, naturalised or invasive in East Africa

Cirsium vulgare is invasive in parts of Kenya (e.g. Kajiado and Laikipia) and has been introduced to Tanzania and Uganda (A.B.R. Witt pers. obs.).

Habitat

Habitats include pastures, abandoned fields, fence rows, areas along roadsides and railroads, cut-over woods, and miscellaneous waste areas. This species prefers disturbed areas and is not common in relatively undisturbed natural habitats.

Description

Cirsium vulgare is a spiny herbaceous biennial, much branched to about 1.5 metres high with a deep tap root.

Stems of C. vulgare have spiny wings. Leaves are dark green, deeply lobbed, with stiff hairs above, white woolly beneath; Leaf lobes end in strong spines. They form a flat rosette.

Flowers of C. vulgare occur in heads of 5 by 5 cm, are pink to mauve and are surrounded by spiny bracts. The fruit is a one seeded tufted  achene that bears silky hairs.

Reproduction and dispersal

Cirsium vulgare reproduces only by seed. The species has a two year life cycle, flowering and setting seed in the second year.  Seeds are short-lived on the soil surface but can persist for many years when they are buried, such as from cultivation activities. Plants can be self-pollinated or insect-pollinated, mainly by long-tongued bees. C. vulgare spreads freely by means of  seed which can be dispersed by the wind over a large area.

Economic and other uses

Cirsium vulgare has medicinal properties and can be used as "survival food" if necessary. However, these uses cannot compensate for this plant's overall negative impacts.

Environmental and other impacts

Cirsium vulgare spreads from pastures, crops, waste areas and roadsides into disturbed native grasslands, open woodlands and conservation areas. Overgrazed pastures are susceptible to encroachment, and it can sometimes form dense stands that reduce productivity and stocking levels.  The species may also dominate forest clear cuts and reduce growth of tree seedlings.

C. vulgare 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) and Hawaii.

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.

Grazing management can help to reduce the ability of Cirsium vulgare to invade pasture lands. Manipulation of grazing together with sowing of appropriate grasses can help to reduce the densities of this weed

C. vulgare only reproduces by seed so control of seed set is key to preventing new infestations.  Flowering stems should be collected and destroyed to keep them from forming viable seed.

Regular cutting, cultivation and tilling considerably reduce populations of C. vulgare and should be encouraged. Several herbicides are available for the control of C. vulgare. However, care should be taken to use a selective broadleaf herbicide to keep the competitive grasses intact.

Biological control releases against C. vulgare have been undertaken in many countries with variable success.

Legislation

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

References

CABI Invasive Species Compendium online data sheet. Cirsium vulgare (spear thistle). CABI Publishing 2011. www.cabi.org/ISC. Accessed March 2011.

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.

PROTA database. Record display PROTA4U: Cirsium vulgare (Savi) Ten. www.prota4u.org/protav8.asp?h=M4&t=Cirsium,vulgare&p=Cirsium+vulgare#Synonyms. Accessed January 2011.

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