| Weed |
Canada
thistle |
| Scientific
Name |
Cirsium
arvense |
| Family |
Aster
family (Asteraceae, formerly Compositae) |
| Life
Cycle |
Perennial |
| Reproduction
Method |
Reproduces
by seed and rhizomes |
| Appearance |
Canada
thistle forms large, coarse plants with spiny leaves. The large, rhizomatous
undergrounnd system forms stems that are grooved and branched at the top,
hairy in youth, smooth when mature. |
| Leaves |
Leaves
of Canada thistle are alternate, long, narrow ovals, with crinkled edges,
spiny margins and pubescent undersides. |
| Flowers |
Borne
July through October and form lavender heads, up to 1" in diameter,
without spiny bracts. Male and fenale flowers are normally on seperate stems
or plants. |
| Occurrence |
Canada
thistles occur on poor, open turf throughout the growing season and are
often more common during cooler seasons. |
| Non
Chemical Control |
To
control Canada thistle without chemicals, maintain turf density and health
through proper culture. |
| Chemical
Control |
 |
 |
| Application
Period |
Apply
postemergence herbicides in mid spring to earlyy summer, mid to late autumn
during periods of active growth. |
| Active
Ingredient in Labeled Products |
Preemergent
|
Postemergent
|
|
|
- 2,4-D
- 2,4-DP
- bentazon
- chlorsulfuron*
- clopyralid
- dicamba
- MCPA
- MCPP
- triclopyr
*not on tall fescue or ryegrass turf |
|
| Notes |
|
(Click
on Image to Enlarge and Sharpen Photograph)
|
Canada
thistle in turf
|
Canada
thistle plant
|
Canada
thistle mature plant
|
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Canada
thistle leaf at stem
|
Canada
thistle seedhead
|
Canada
thistle leaf underside
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| Confused??
Look-a-Likes |
|
