Hairy Bittercress

Hairy bittercress (photo by Kate St. John)

Every spring I'm stumped by this small flower that blooms in lawns, fallow gardens and waste places.  With four petals and alternate "divided" leaves I could tell it's in the Mustard family.  When I keyed it out in Newcomb's Wildflower Guide I arrived at Pennsylvania bittercress (Cardamine pensylvanica*).

But that's not what it is.   It grows too well in poor soil to be a plant known for preferring wet habitats, swamps and stream banks.  I began to suspect it's an alien.

Based on that hunch I sent photos to friends.  Mark Bowers answered that this is hairy bittercress (Cardamine hirsuta), native to Europe and Asia.

Like Pennsylvania bittercress, its young leaves can be used in salads and are said to taste like radishes.


(photo by Kate St. John)

* Not a typo, the person who classified Cardamine pensylvanica omitted the second 'n' in our state's name.

9 thoughts on “Hairy Bittercress

  1. Careful pulling this plant when the seed pods are ripe….they explode with tiny seeds that can get in the eyes! Thanks for finding the info on this plant Kate!!!….I’ve been wondering what it is for around 8 years now…it seemed to just “suddenly” show up everywhere… kind of like garlic mustard…

  2. Yes, the exploding seed pods (characteristic of mustards) are what makes it so invasive. I’d been told it was PA bittercress, but perhaps this sudden apparition (greatly increasing over the past few years) is due to its alien identity…

  3. I hate this plant and thought it was the PA Bittercress..sorry, I don’t think I will try to eat it, esp since the deer and the rabbits don’t…I have gotten seeds in my eyes from them exploding…so since it rained they are getting pulled As Fast As Possible before they seed and not put in the compost..

  4. I too hate this plant — when the seeds explode & go everywhere, I can just see more & more of the little plants growing. It is fairly new, isn’t it — I never noticed it before 2 – 3 years ago. Does spraying help, rather than pulling the weeds? i.e. do they die, or will they still continue to spray the seeds?

  5. Libby….
    Just some of my observations….The seeds germinate in mid fall…pre-emergent control would need done at beginning of fall.
    The plant does grow a rosette over winter…seems very happy with the cold.. but it “blends in” as the leaves are dark and flat against the ground…
    By late winter the stalks that hold the flowers pop up in the first thaws and in two or three warm days they bloom…setting seedpods as the bloom stalk grows higher…
    Spraying takes to long….I’ve tried it but they set seed before they die…
    I did try vinegar on some…it burned them up 🙂 but they re-grew from the root… 🙁

  6. I’m glad you told me that, carrolltown OH. I spent a lot of time last spring spraying as many as I could of this pesky weed. This spring, I won[t wast my time. So — how to get rid of them?

  7. Libby…your welcome!…try a form of pre-emergent seed inhibiter…Check at a reputable garden center near you for help…
    Get either the organic or chemical pre-emergent soon…but wait till fall starts before you put it on, because it will not be effective by fall…. if you put it on now…

    Hand pull what you can, but bag them up! They are hardy plants and set seed pulled or not!

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