Click on image to enlarge
|
DESCRIPTION:
Canada thistle, a perennial, is found in most of the western states. The
extensive root system may be 20 feet (6 m) deep and reach 15 feet (4 .5 m)
horizontally. White to purplish pink flower heads, about 1/2 inch (1.3 cm) in
diameter, form on separate male and female plants. Wind dispersed seeds can
be viable for many years when buried. Seedlings start forming perennial
rootstock when they are 3 weeks old or have five leaves. Plants will also
grow from cut roots. Plants have a basal rosette of spine-tipped, wavy
leaves with alternate leaves mostly stalkless along the stem. Control
plants before they can regenerate food reserves or produce seed. Prevent
spread to new areas and eliminate the weed from noncrop locations.
Broadleaf ID illustration.
|
