Conium maculatum is a highly poisonous biennial herbaceous flowering plant native to Europe and North Africa. A hardy plant capable of living in a variety of environments, hemlock is widely naturalized in locations outside its native range.
A herbaceous biennial flowering plant that grows to 1.5–2.5 m (5–8 ft) tall, with a smooth, green, hollow stem, usually spotted or streaked with red or purple on the lower half of the stem. All parts of the plant are hairless (glabrous); the leaves are two- to four-pinnate, finely divided and lacy, overall triangular in shape, up to 50 cm (20 in) long and 40 cm (16 in) broad. It has been introduced and naturalised in many other areas, including Asia, North America, Australia, and New Zealand. It is often found on poorly drained soils, particularly near streams, ditches, and other surfaces water. It also appears on roadsides, edges of cultivated fields, and waste areas. It is considered an invasive species in 12 U.S. states.
It is used as a food plant by the larvae of some Lepidoptera species.