Weeds: Sowthistle, annual and perennial – Sonchus oleraceus, Sonchus arvensis

• Family: Asteraceae (Compositae)
• Cycle: Annual
• Plant type: Broadleaf

Biology

Annual sowthistle grows upright and can reach from one to four feet tall. The lower leaves have a stalk while the upper leaves do not. Most of the leaves are deeply lobed and have one to three lobes on each side. Annual sowthistle produces many pale yellow flower heads that are 1/4 to 3/4 inch wide. The seeds are flat with lengthwise ribs and a parachute-like tuft of fine hairs that aid in wind dissemination. Perennial sowthistle leaves, stems, and flowerheads are often a little larger than annual sowthistle. Perennial sowthistle produces many creeping roots that aid the spread of this creeping perennial species.

Habitat

Sowthistle grows along roadsides, cultivated fields, in gardens and in waste areas throughout Washington.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• None recommended

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Glyphosate products should be applied as spot treatments only!
• NOTE: Some ingredients listed here are only available in combination.
• Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Additional Images