Scientific Name: Sonchus asper

Common Name: spiny sowthistle

Synonyms: Sonchus nymanii

Leaves: Annual sowthistle is a summer annual plant which can grow up to 5 feet in height. It blooms from late spring through early fall and reproduces by means of seeds.

Identifying Characteristics: The parachute of the seeds has allowed for the wide spread dispersal of annual sowthistle. Among its defining characteristics are stiff, spined leaves which clasp at the stem.

Flower Seed Head: The flowers of annual sowthistle are yellow in color and approximately 1 inch in diameter. They bloom from late spring through early fall.

Seed Fruit: The seeds of annual sowthistle are, on average, 3 mm long and 2 mm wide. They are tan in color and have a small parachute of hairs which allows for easy dispersal.

Where Found: Annual sowthistle has spread throughout the majority of the United States. It is also present in many other countries, including in Europe and the rest of North America.

  • Life cycle: summer annual

  • Milky sap: Present

  • Plant type: Herb

  • Thorns: Present

  • Plant family: Asteraceae

  • Leaf arrangement: alternate; rosette

  • Leaf shape: oval; spatulate

  • Ochrea: Not Present

  • Leaf margin: entire; lobed; serrated

  • Stem hairs: has hairs; no hairs

  • Flower color: yellow

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: no hairs; has hairs

  • Flower symmetry: radial symetery

  • Flower diameter: nickle; half dollar; quarter

  • Root structure: fibrous; taproot

  • Leaf stalk: none