View photos of the medicinal plant Potentilla fruticosa [Dasiphora fruticosa] (Bush cinquefoil), profiled in Medicinal Plants of the Western Mountain States (as Potentilla spp.).

A passage from Medicinal Plants of the Western Mountain States:

As a curb for excessive menstruation and mid–cycle spotting, Cinquefoil has a long history of use. It will be found most effective if the situation is due to constitutional tendency or idiosyncratic biorhythm discombobulation.