|
|
|
|
Perennial Sowthistle (field
milk-thistle)
Asteraceae (=Compositae), the aster family
|
Background
|
 Perennial sowthistle is native to western Asia and
Europe. It spreads both by seed and creeping roots, and it grows under a
many conditions. Plants produce from root buds as deep as 2 feet, often
resulting in large, dense colonies.
|
Description
|
Perennial sowthistle has
crowded, spatula-shaped to deeply lobed, dandelion-like leaves up to 10
inches long near the base of the plant. Stem leaves are much reduced,
usually unlobed,
 and scarce; all leaves are prickly toothed along the
margins. Stems are hollow, sparsely branched, and up to 6 feet tall. Both
leaves and stems exude a milky latex when broken. Yellow, dandelion-like
flower heads are 2 inches wide and bloom from June until frost. The flower
heads and their stems bear coarse, spreading, gland-tipped hairs. Seeds are
reddish brown, 1/8 inch long, flattened, ribbed, and tipped with white
plumes. The plant has extensive horizontal roots.
|
Distribution
|
 Perennial sowthistle is present in the northern U.S.,
and in California, Texas, Missouri, and North Carolina.
|
Control
|
|
No biological control agents are available, but herbicides are. |
|
© 1999 University of Idaho:
Text and photographs for these pages from Idaho's Noxious Weeds, by
Robert H. Callihan and Timothy W. Miller (revised by Don W. Morishita
and Larry W. Lass).
Please contact: Ag Publishing, University of Idaho, Moscow,
Idaho 83844-2240; 208 882-7982 visit the Resources for Idaho website at
http://info.ag.uidaho.edu, for more information about this or other
publications.
|
|
|
|
|
|
