Tansy - How to Control it and Discussion

Tansy grows to be a large successful bush covered with yellow flowers. It is considered invasive and poisonous to cattle. I have heard some say that is a valuable herb. I would like to get ideas on how to kill a Tansy plant. I am also interested in the controlled growth of Tansy and use as a herbal.


  • LaurieLovesLearning
    LaurieLovesLearning Posts: 7,210 admin
    edited October 2020

    @flowerpower * Here is a past discussion that likely has the answers that you are looking for.

    I certainly do have a very invasive variety and what appears to be a less invasive variety (but where it is, it is persistent & hard to dig all of it up).

    I have been fighting the super invasive variety for 15 years. The roots are strong and hold the ground well. The roots are tough. I had to dig deeply when the ground was saturated and revisit the area later as every little root you leave will grow a new plant. I would cut the plant into pieces over a black garbage bag, making sure that no portion of the plant was left behind. Then, I then tied the bag up tightly and let it bake in the sun.

    The seeds are viable up to 15 years. You will find many baby plants hiding everywhere, far from where you would have ever thought. Dig those up immediately when they are found, along with a bunch of soil around the roots.

    The buttons are persistent. If you cut the plant back, it will just grow those further down.

    I have no idea which type either are, but unless you know you want it for a very long time and are willing to fight an endless battle if you get the wrong one, font buy the seed. I have wished over many years that I never bought them.

    I think that I am finally winning the battle. I counted only 5 plants left this past fall. I hope that that is all I have throughout next year.

    A note on cattle & horses...they won't eat it unless there is inadequate food otherwise. Ours didn't eat it. It also won't kill them immediately. If I remember correctly, it will store in the liver (and stay in there) until there is too much & they die of poisoning. My understanding is that it is fatal.

    It is also poisonous to humans. Tansy tea is not recommended and poisonings have been reported. It smells horrible anyway. I think the tea would be nasty. You are supposed to handle it with gloves as it can affect your health negatively. I think reproductively? My memory could be wrong with that part. It saves your hands from being smelly nevertheless.

    If you don't mind, I am going to close this thread. Please continue the discussion in the thread above. It is nicer if we can keep things in one place when possible. Thanks!

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