Euphorbia characias ssp. wulfenii is an evergreen perennial native to southern Europe that grows 3-5 feet tall. In spring, its erect stems carry large clusters of chartreuse flowers. All parts of the plant are poisonous and its milky sap can irritate skin, so it should be planted away from children and pets. It is deer resistant and can be used to naturalize or for bold displays in mixed plantings with sun to part shade and well-drained soil needing only occasional watering.