Artichoke Thistle belongs to the family Asteraceae and is a form of herb. A perennial or biennial spiny thistle with annual topsĀ and a cluster of large bright purple flowers that are 5-8 cm in diameter during summer. The mature plant is erect, with stems 1-1.5 (2) m tall arising from a bushy rosette up to 2 m wide and tall. The stem is strongly ribbed and covered with downy grey hairs and usually single at the base and branched towards the top. The large, grey green leaves are deeply lobed and spiny with woolly hairs underneath.