Municipal Plant of the Month – Bugweed, Luisboom: Solanum mauritianum.
Bugweed is a Category 1b invasive species which must be removed and destroyed. Any form of trade or planting is strictly prohibited.
Impacts: Robust, long-lived (up to 30 years) and fast-growing – easily reaching a height of 3-5m, shading out other vegetation. It can flower year-round but fruiting occurs in late spring to early summer. It is tolerant of many soil types and quickly becomes established around plantations, forest margins, scrub and open land. All parts of the plant are poisonous – in particular the unripe green berries. Birds, which are unaffected by the poison, act as seed dispersers.
Identification: A large untidy straggly shrub with distinctive large dull grey-green leaves that are velvety above with white felty undersides. The leaves have an off-putting scent. Clusters of purple flowers with yellow centres occur throughout the year. The fruits are borne in compact terminal clusters of berries of 10 mm across, turning yellow when ripe.
Control: Felling and treating the stump with the herbicide Timbrel or Kaput easily kills bugweed. Alternatively, the stump can be frilled and the frill treated with the same herbicide. Any clearing must have a follow-up program to address the inevitable seed germination.
References: www.invasives.org.za : www.sanbi.org : www.gpwonline.co.za/ Gazettes/Gazettes/37886_1-8_EnvAffairs.pdf – p.29 : www.george .org.za/page/environmental_affairs (search under COMMUNITY SERVICES and NEWS tabs.