Lantana camara (Verbenaceae)

Lantana is one of the worst weeds in the world, according to the ARC Plant Protection Research Institute. It is a category 1b species in South Africa under NEMBA.
Land occupiers are legally obliged to control it, or to remove and destroy it if possible. No trade or planting is allowed.
Lantana was introduced into Cape Town in 1858 and in 1954 it was declared a noxious weed throughout South Africa.
Owing to the fact that it is tolerant of herbivory, drought, frost and fire, and secretes chemicals that suppress competitors, it has the ability to dominate pre-existing vegetation.
Young stems are prickly, and almost square. The serrated, opposite leaves are rough, and pungent when bruised. Flower-heads are multi-coloured, with florets opening yellow or white and becoming pink, orange or red. Clusters of berry-like fruits turn blackish when ripe.
In agriculture, impenetrable thickets of lantana replace natural pasturage and reduce the productivity of stock farming. Since most of the plant is toxic, it can also poison cattle. Furthermore, lantana suppresses biodiversity and lowers land values.
Since each variety differs in physiology, toxicity, susceptibility to herbicides and natural enemies, lantana is extremely difficult to control or kill. After slashing or spraying herbicide, the plants may die back and appear dead, but seeds in the ground germinate and grow, the stumps soon re-sprout, more seed is produced, and the infestation becomes denser and more widespread.
While biological control is the only potentially sustainable solution, the agents collected from the wild lantana species thus far are not sufficiently effective in controlling the weedy hybrids. The only way to get rid of lantana is to apply a rigorous combination of mechanical plus chemical control and annual follow-up treatment.
Lantana rugose however is indigenous and non-invasive.