What Thistle (Canada and Bull) looks like
Spiky, deeply-lobed purple leaves with prickly margins and purple-pink thistle flowers; grows 2–4 feet tall.
Photo: Wikimedia Commons
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Best approach: Herbicide spray
Canada thistle has an extensive root system — digging usually fails because any root fragment left behind regrows. Spray with triclopyr or glyphosate (spot-treat) for best results. Wear thick gloves due to spines.
Best products for Thistle (Canada and Bull)
Formulated to kill thistle (canada and bull) without wiping out your grass — see the timing and chemistry below.
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BioAdvanced All-In-One Weed & Feed (22-0-4)
✓ Kills thistle (canada and bull)Beginner friendly
Scotts Turf Builder Triple Action1
✓ Kills thistle (canada and bull)Beginner friendlyPrevents crabgrass for up to 4 months, kills dandelion, clover and other listed broadleaf weeds, and feeds. Apply to wet grass, no more than twice a year. Not for St. Augustine. Its label allows centipede, but centipede does better with a stand-alone weed killer and a lighter feeding.
Scotts Turf Builder Weed & Feed5
✓ Kills thistle (canada and bull)Beginner friendlyWeed killer plus 26-0-2 lawn food for dandelion, clover and other listed broadleaf weeds. Apply to wet grass. On bahia, wait until mid-April and the third mowing, and make fall applications before Nov 1. Not for St. Augustine. Its label allows centipede, but centipede does better with a stand-alone weed killer and a lighter feeding.
How much do you need?
Herbicide is dosed by lawn size. Pick your yard size for a quick estimate:
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When to treat Thistle (Canada and Bull)
Spray in spring or fall when temperatures are 60–80°F and the weed is actively growing. Avoid summer heat — stressed grass takes collateral damage.
Chemical treatment
Spot-treat with glyphosate when actively growing in spring or early summer, or use a strong broadleaf herbicide (2,4-D + dicamba or triclopyr) in fall. Repeat as needed.
Non-chemical management
Remove flowers before they set seed; maintain turf density to prevent thistle establishment.
How to stop Thistle (Canada and Bull) coming back
Remove flowers before they set seed; maintain turf density to prevent thistle establishment.
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What does Thistle (Canada and Bull) look like?
Spiky, deeply-lobed purple leaves with prickly margins and purple-pink thistle flowers; grows 2–4 feet tall.
What's the best way to kill Thistle (Canada and Bull)?
Herbicide spray. Canada thistle has an extensive root system — digging usually fails because any root fragment left behind regrows. Spray with triclopyr or glyphosate (spot-treat) for best results. Wear thick gloves due to spines.
Is Thistle (Canada and Bull) hard to get rid of?
Thistle (Canada and Bull) is rated hard to control. It usually requires multiple applications and a consistent plan.
How do I stop Thistle (Canada and Bull) coming back?
Remove flowers before they set seed; maintain turf density to prevent thistle establishment.
Other broadleaf weeds
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