The Shrubby Cinquefoil (Dasiphora fruticosa, syn. Potentilla Fruticosa) may be the plant on fol. 23r of the Voynich Manuscript. Ironically, the shrubby cinquefoil comes with flowers in about every other color but blue. Other than that, it is a pretty good match. In Mary's Garden lists potentilla is often associated with Our Lady's fingers.