Humans’ exploitation of the plant kingdom through the ages can be described as a reshufﬂing of species around the globe in a giant game of botanical chess. The vast increase in global trade, travel, and communications in the last two hundred years has contributed to this mixing and exchange of plants around the world (McNeely 2001). While some of these introductions are accidental, agriculture and horticulture in most parts of the world are mainly dependent on species that have been deliberately introduced from other regions. Some of these plants that are brought into cultivation, whether for agriculture, forestry, or ornament, escape from where they are grown and become naturalized, replacing native vegetation. Such plants are known as invasives or plant invaders (Cronk and Fuller 1995) and form part of the group called Invasive alien species (IAS)—non-native organisms that cause, or have the potential to cause, harm to the environment, economy, or human health. They have been described as one of the most signiﬁcant drivers of environmental change worldwide.