The Jerusalem artichoke (Helianthus tuberosus L.) is an erect, rhizomatous perennial herb, up to 3-4 m high. Though perennial, it is mainly grown as an annual. It is a highly variable plant: many characteristics, including size (2 to 4 m), tuber colour (green or violet), stem number and the number of branches per stem depend on genetics and environmental conditions. The stems are generally hairy and branch in their lower part. The root system is fibrous and develops cord-like rhizomes that can reach more than 1 m in length. The apical part of the rhizome is swollen and forms a fleshy tuber. The leaves are opposite or alternate, ovate to lanceolate, toothed, pubescent on the lower surface and 3-20 cm long x 5-8 cm broad. The inflorescence is a pseudanthium borne alone or in groups at the end of the stem or on terminal axillary branches. The flower head is 5-11 cm in diameter (much smaller than that of the sunflower) and bears many small yellow tubular fertile flowers surrounded by yellow ray sterile flowers, the ligules of which are thought of as petals. The fruit is a hairy achene containing a mottled black or brown seed, 5 mm long x 2 mm wide
It can be invasive in the Mediterranean region.