Wednesday, November 26, 2014

Coastal BC Plants: Bull Thistle

Bull Thistle

The very prickly Bull Thistle (Cirsium vulgare) can be found along roads, and in fields and disturbed areas such as logging slashes. I found this specimen on a logging road near Chippewa Bay on Powell Lake.

Bull Thistle is an invasive species introduced from Euroasia. It's considered a noxious weed because it can spread easily in fields, keeping stock from grazing, and can contaminate hay.

Bull Thistle is a member of the Aster Family. It's widely distributed throughout Canada and the United States. It's a biennial plant (taking two years before going to seed) that can grow up to two metres tall. Rigid upright stems have spine tipped leaves. Thistle heads are surrounded by spines and sport bright pink to purple flowers.

Seeds are dispersed by wind on silky down. They are very viable, assisting the spread of this weed. There are few natural enemies to keep it in check. The Bull Thistle is sometimes misidentified as the Canada Thistle. Both have those beautiful bright flowering heads. Goes to show, there's always something good, even in the bad. -- Margy


  1. Very interesting post. Didn't know it was invasive.

  2. Hi Margy! Oh those nasty Thistles. We have pretty much eradicated them on our property. Oh they pop up now and then but chop 'em down. Funny thing is the horses will eat them chopped down but won't go near them growing.

  3. The colour of thistles is very striking and beautiful. Florists often use them in bouquets. They are very decorative, but I can understand that too many of them is bad.
    Thanks for your visit.
    Have a great weekend.
    Wil, ABCW Team.

  4. What a shame that such a pretty little weed is so deadly, the colour is so vivid.
    Of course, being British one always identifies the Thistle with Scotland b the Scots national emblem.

    Best wishes,
    ABCW team.

  5. it is one of my favorites in spite of it's thorniness. It is the flower of Scotland.

  6. pretty but prickly?


  7. Thanks everyone for stopping by my post about Coastal BC plants. I have been learning so much doing this series.

    MargyBeth - I'm surprised horses will eat the cut thistle plants. I would think it would prick their tender mouths.


  8. We have something like this too and they are full of prickly spines. They are pretty but I don't like them.

  9. I saw plenty of beautiful thistles blooming while I was in Ottawa in August. I didn't realize there are 2 different types that look so similar - now I will have to find out what kind they were.

  10. Susan - There are lots more types of thistles according to my research, but they are all prickly. Of course, we enjoy eating artichokes, another kind of thistle.

    Kathy - I've seen thistles in lots of places and climates. Maybe their method of reproducing with silky down makes them spread easily.



We welcome your comments and questions. - Wayne and Margy