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  2. Extension and Outreach
  3. Plant ID
  4. Broadleaf Weeds
  5. Canada Thistle

Canada Thistle

Image courtesy of the slide collection of Jack Harper.

Canada Thistle

Image courtesy of the slide collection of Jack Harper.

Image courtesy of Jeffrey Borger.

Canada Thistle

Image courtesy of Jeffrey Borger.

Image courtesy of Jeffrey Borger.

Canada Thistle

Image courtesy of Jeffrey Borger.

Image courtesy of Jeffrey Borger.

Canada Thistle

Image courtesy of Jeffrey Borger.

Image courtesy of Jeffrey Borger.

Canada Thistle

Image courtesy of Jeffrey Borger.

Image courtesy of Matthew Naedel.

Canada Thistle

Image courtesy of Matthew Naedel.

Spines. Image courtesy of Matthew Naedel.

Canada Thistle

Spines. Image courtesy of Matthew Naedel.

Mother and daughter plant spread by rhizome. Image courtesy of Matthew Naedel.

Canada Thistle

Mother and daughter plant spread by rhizome. Image courtesy of Matthew Naedel.

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Plant Identification

  • Plant Identification Overview
  • Broadleaf Weeds
    • Broadleaf Weeds Overview
    • Aster, Whiteheath
    • Brambles
    • Buckwheat, Wild
    • Burcucumber
    • Burdock, Common
    • Buttercup, Tall
    • Butterfly-weed
    • Carrot, Wild
    • Catchfly, Night-flowering
    • Chickweed, Common
    • Chickweed, Mouseear
    • Clover, White
    • Cinquefoil, spp.
    • Chicory
    • Coltsfoot
    • Cornmint
    • Cornspurry
    • Cucumber, Wild
    • Daisy, Ox-eye
    • Dandelion, Common
    • Dock, Broadleaf
    • Dock, Curly
    • Dogbane
    • Dogfennel
    • Evening Primrose, Cutleaf
    • Fern, Eastern Bracken
    • Filaree, Redstem
    • Galinsoga, Hairy
    • Geranium, Wild
    • Goldenrod, Canada
    • Goosefoot, Nettleleaf
    • Ground Cherry, Clammy
    • Groundsel
    • Hawkweed, Yellow
    • Healall
    • Hemlock, Poison
    • Hemp, Sesbania
    • Henbit
    • Horsetail, Field
    • Ivy, Ground
    • Ivy, Poison
    • Jimsonweed
    • Knotgrass, German
    • Knotweed, Prostrate
    • Kochia
    • Ladysthumb
    • Lambsquarter
    • Lettuce, Prickly
    • Medic, Black
    • Mallow
    • Marestail
    • Mayweed
    • Milkweed
    • Morning-glory
    • Mugwort
    • Nightshade, Bitter
    • Oxalis
    • Plantain, Bracted
    • Plantain, Broadleaf
    • Plantain, Buckhorn
    • Passion Flower
    • Pea, Partridge
    • Pear, Prickly
    • Pearlwort, Birdseye
    • Pennycress, Field
    • Peppervine
    • Pigweed, Redroot
    • Pineapple-weed
    • Pokeweed, Common
    • Purslane
    • Ragweed, spp.
    • Redmaids, Fringed
    • Rocket, Yellow
    • Scarlet-pimpernel
    • Shepherds-purse
    • Sicklepod
    • Smartweed, Pennsylvania
    • Snakeroot, White
    • Snow on the Mountain
    • Sorrel, Red
    • Sowthistle, Perennial
    • Spanish-needles
    • Speedwell, Creeping
    • Speedwell, Ivyleaf
    • Speedwell, Thymeleaf
    • Sprangletop, Red
    • Spurge, Leafy
    • Spurge, Prostrate
    • Spurge, Spotted
    • Starbur, Bristly
    • St. Johnswort
    • Sumac, Poison
    • Swinecress
    • Thistle, Bull
    • Thistle, Canada
    • Trefoil, Birdsfoot
    • Trumpet-creeper
    • Velvetleaf
    • Verbena, Bigbract
    • Verbena, Sandpaper
    • Yarrow
    • Vetch, spp.
    • Violet
    • Watermelon, Wild
    • Whitlowgrass, Early
    • Witchweed, Asiatic
  • Grasses and Sedges
    • Grasses and Sedges Overview
    • Barnyardgrass
    • Barley, Little
    • Bentgrass, Creeping
    • Bluegrass, Annual
    • Bluegrass, Kentucky
    • Bluegrass, Rough
    • Bromegrass, Downy
    • Cane, Wild
    • Crabgrass, Smooth
    • Dallisgrass
    • Dayflower, Asiatic
    • Fescue, Fine spp.
    • Fescue, Tall
    • Foxtail, Green
    • Foxtail, Giant
    • Foxtail, Yellow
    • Goosegrass
    • Johnsongrass
    • Nimblewill
    • Nutsedge, Yellow
    • Onion, Wild
    • Orchardgrass
    • Panicum, Fall
    • Quackgrass
    • Rush, Toad
    • Ryegrass, Perennial
    • Sandbur, Field
    • Signalgrass, spp.
    • Smutgrass
    • Stinkgrass
    • Velvetgrass, Common
    • Witchgrass
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