|
|
Musk Thistle Asteraceae
(=
Compositae), the aster family
|
Background
|
 Musk
thistle, a native of Eurasia, was probably introduced into the U.S. as an
ornamental in the early 20th century. It spreads by seeds, often forming
nearly impenetrable stands. It can grow under a wide range of environmental
conditions.
|
Description
|
Musk thistle is a biennial or winter
annual that can
grow up to 8 feet tall. Leaves are up to 10 inches long, dark green with a
light green midrib, and spiny and deeply
lobed. Solitary, lightly spiny , and
nodding flower heads develop at the stem tips in midsummer, and grow to a
diameter of 11/2 to 3 inches. Blossoms are deep rose to violet or sometimes
white in color. Seeds are 3/16 inch long, shiny, yellowish brown, and have a
hair-like plume.
|
Distribution
|
 Musk
thistle is widely though sparingly present in North America and is present
in northern, central, and eastern Idaho counties.
|
Control
|
Biological control agents (a seed head weevil and a rosette
crown weevil) have provided good control of musk thistle.
Herbicides offer effective control |
|
© 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.
|
|
|
|
