| perennial sowthistle | USDA PLANTS Symbol: SOAR2 U.S. Nativity: Exotic Habit: Forbs/Herbs |
| Sonchus arvensis L. |
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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae |
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| Synonym(s): field sowthistle, creeping sowthistle, field sow-thistle | |
Perennial sowthistle is a perennial herb native to Eurasia. Stems can reach 4.9 ft. (1.5 m) in height and contain milky sap. Leaves are sessile, alternate, clasping, up to 12 in. (30 cm) long and decrease in size further up the stem, margins undulate with sharp spines. Flowering occurs in June to October, when yellow, tight, dandelion-like flower heads develop at the tips of the branches. Flowers open 2-3 hours after sunrise and close about noon. Fruits are reddish, ribbed and have a tuft of hair (pappus) at the top. Perennial sowthistle occurs along roadsides, railroads and other disturbed habitat. |
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Identification, Biology, Control and Management Resources
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| Selected Images from Invasive.org | View All Images at Invasive.org |
 Plant(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Foliage; Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Foliage; Richard Old, XID Services, Inc., Bugwood.org Additional Resolutions & Image Usage |
 Feature(s); Stem Michael Shephard, USDA Forest Service, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Theodore Webster, USDA Agricultural Research Service, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Ohio State Weed Lab Archive, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Tom Heutte, USDA Forest Service, Bugwood.org Additional Resolutions & Image Usage |
 Flower(s); Richard Old, XID Services, Inc., Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); Ken Chamberlain, The Ohio State University, Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); David Cappaert, Michigan State University, Bugwood.org Additional Resolutions & Image Usage |
 Fruit(s); S. oleraceus on left; S. arvensis on right Steve Dewey, Utah State University, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); in flower Michael Shephard, USDA Forest Service, Bugwood.org Additional Resolutions & Image Usage |
 Plant(s); in flower Michael Rasy, University of Alaska, Bugwood.org Additional Resolutions & Image Usage |
| EDDMapS Distribution: This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org |
 State(s) Where Reported invasive. Based on state level agency and organization lists of invasive plants from WeedUS database. |
| U.S. National Parks where reported invasive: |
| Rocky Mountains National Park (Colorado) Yellowstone National Park (Wyoming) |
| Invasive Listing Sources: |
| Faith Campbell, 1998 |
| Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007 |
