Common Sowthistle

Asteraceae

LIFE FORM: Summer annual

NATIVITY: Europe

VEGETATIVE CHARACTERISTICS:

An unbranched plant with smooth, erect stems that can reach up to 6 feet in height; all parts of the plant exude a white sap when cut; stems and foliage appear succulent and waxy white or bluish (glaucous); pinnately lobed leaves have margins that are slightly prickly.

FLOWERS:

The plant elongates in summer and produces terminal clusters of bright yellow composite flowers about an inch in diameter.

FRUIT/DISPERSAL AGENTS:

Small seeds have a feathery pappus that aids wind-dispersal.

ECOLOGICAL PREFERENCE:

Grows best in rich soil in full sun. Prefers neglected residential and commercial landscapes; minimally maintained public parks and open space; vacant lots and rubble dump sites.

ENVIRONMENTAL FUNCTION:

Disturbance-adapted colonizer.

CULTURAL SIGNIFICANCE:

This plant is difficult to distinguish from perennial sowthistle Sonchus arvensis that reproduces from root suckers. Listed by John Josselyn in New-England’s Rarities, published in 1672, under the category: “Of such plants as have sprung up since the English planted and kept cattle in New England.” Included by Greek physician Pedanius Dioscorides in his five volume herbal, De Materia Medica, which was written in the first century AD and remained in active use into the 1600s.