
Urban Species #033: Cinquefoil
Potentilla canadensisNo, it's still not spring, but we are at the halfway point between Winter Solstice and Vernal Equinox. But this little weed belongs to a group of hardy plants called "cinquefoils" no matter how many leaves they have (the name is French for five leaf), though they usually have three, five, or seven. The scientific name potentilla means "little powerful one" which says more about the symbolism of the number five than it does about the plant itself. Being in the rose family, cinquefoils have five-petaled flowers, further emphasizing the "five" symbol. Cinquefoils are high in tannins, making them useful herbs in those applications requiring an astringent.
There are 300 species of cinquefoil worldwide, over 100 of them occurring in North America. The most common urban species are
P. simplex ("common cinquefoil"),
P. canadensis ("dwarf cinquefoil") and
P. recta ("sulfur cinquefoil.") This last one I see most often, with a pale sulphur yellow flower, instead of the bright buttercup yellow flower that the others have. Sulphur cinquefoil is native to Europe, and is considered invasive in several western states.
Dwarf and common cinquefoils thrive as weeds in lawns, low enough to be passed over by the mower and bad tasting to many herbivores.