Perennial sowthistle (Sonchus arvensis ssp. arvensis)

Gallery:

Common names:

Perennial sowthistle

Scientific Name:

Sonchus arvensis ssp. arvensis (syns. Sonchus arvensis var. shumovichii)

Description:

A deep-rooted perennial herb, perennial sowthistle has upright, hollow stems with bitter, milky juice. Flowerheads are bright yellow and 1.5 inches wide. Flowers open 2 to 3 hours after sunrise and close around noon. Bracts at the base of flowerheads are green, bristly and have sticky hairs.

Life cycle:

Perennial

Height of mature plants

1.5 feet to 6 feet

Flower color:

Yellow

Bloom time:

March through June

Look-a-likes:

Common sowthistle, Sonchus oleraceus, is similar but is an annual species.

Habitat:

Perennial sowthistle is found in a variety of places such as cultivated fields (both grain and row crops), waste areas, meadows, sloughs, woods, lawns, roadsides, beaches, ditches as well as river and lake shores.

Impacts:

Perennial sowthistle is classified as a noxious weed in many states and provinces. It is a problem in several crops where it causes economic losses due to reduced crop yields, increased cultivation and herbicide expenses and land depreciation.

Noxious Weed Listing:

Origin:

Europe, Asia and Northern Africa

Links:

Washington Noxious Weed Profile
Invasive.org profile
CABI Invasive Species Compendium

 

WeedWise Program