The shrub tobacco

The tobacco tree is another alien species that has found its way to the Maltese Islands as a cultivated decorative plant. 

It is now found in the countryside especially in rubble, building sites old walls and fortifications. It was originally native of Bolivia, Paraguay and Argentina but has now become naturalised in many parts of the world especially around the Mediterranean and southwestern United States.

Known in Maltese as tabakk tas-swar, this species is actually a small tree that usually grows up to about two metres but which can sometimes be more than seven metres high. The shrub tobacco is also known as the glaucous tobacco and by many other names including mustard tree, Brazilian tree tobacco and tree tobacco.

In warm climates it flowers all year round and produces large quantities of seeds. In Malta the long and narrow yellow flowers are seen mostly between spring and autumn.

The shrub tobacco is an invasive species and in many areas where it has been introduced it is considered as a pest and action is taken to eradicate it because of its ability to displace indigenous species. In other areas it is considered as a medicinal plant and is even used to produce biofuels.

It is related to the tobacco plant which is the source of the tobacco used for smoking. In fact both belong to the Nicitiana family a name given in honour of Jean Nicot (1530-1600), a French diplomat, who is said to have introduced tobacco to Europe as snuff (powdered tobacco that is sniffed up the nostril) to the French court.

Shrub tobacco is being studied as a potential treatment for nicotine addiction since it does not contain nicotine, but similar chemicals.  It is claimed that the leaves are smoked for ritual purposes by the Navajo Indians however, smoking and/or ingesting the plant has lead to death as all parts of the plant contain chemicals that have insecticidal properties which make all parts of the plant extremely poisonous and thus unpalatable to insects and other animals.