Gomphocarpus fruticosus (swan plant; narrow-leaved cotton bush) is a species of plant native to South Africa. It is also common in Australia and New Zealand where it is a host of the monarch butterfly. The plant's tissues contain sufficient cardenolides that consumption of significant quantities of the plant's leaves, stems, or fruit may lead to death in livestock and humans. The plant, also referred to as Narrow leaf cotton bush, has officially been declared a pest in Western Australia. The species is closely related to Gomphocarpus physocarpus.