Ruta graveolens

Besides being a tough and easy perennial with attractive blue leaves, Rue is a valuable garden plant. A number of species of Swallowtail butterflies use it as a larval host plant. It was tabbed as the “Herb of Grace” By William Shakespeare, as it was used to sprinkle holy water before High Mass. The tip of Rue’s leaf was the model for the suit of clubs in playing cards. A few people have a skin reaction to its sap when exposed to sunlight.