Those seeking the elusive lesser celandine (Ranunculus ficaria) should time their search carefully in the spring, as the plant remains hidden underground outside of its flowering period. The plant’s club-like rootstocks can be found hidden in the clay soil by the shores of the river Vantaanjoki as well as on the Pihlajasaari islands, Vallisaari island and many other islands off the coast of Helsinki, where they were most likely transported to by humans to cultivate as decorative plants.