This is a beautiful photograph, but I don't think it's C. hirsuta. C. hirsuta has four stamens and I count at least five in these flowers. It could be C. flexuosa, which has six stamens, two of which are shorter than the others. This reference has a useful key to weedy Cardamine spp. http://www.lib.ncsu.edu/theses/available/etd-07112008-145744/unrestricted/etd.pdf
