Also known as rock poppy, wartwort, tetterwort, nipplewort, and swallowwort, this herbaceous biennial or short-lived perennial is native to Europe and western Asia but has been introduced as an ornamental to North America where it has become an noxious/invasive weed in some areas. It is a member of the poppy family, Papaveraceae, that also includes bloodroot, bleeding heart and corydalis. The plant forms clumps up to 1-4′ tall, is branched and has smooth or slightly hairy, brittle stems that when broken or bruised exude an acrid orange to yellow sap that can cause irritation and blistering of the skin. The blue-green leaves are 5-12″ long, pinnately lobed or divided, and have irregularly scalloped margins. From late spring through summer, loose, terminal, umbel-like clusters of 4 flowers appear. Each flower is up to 1″ wide and usually has 2 sepals, 4 yellow petals and a mass of yellow stamens, but double flowered forms occur naturally in nature. The fruit is a 2″ long, cylindrical capsule containing many small white-tipped black seeds. Plants aggressively self seed and should be grown in a place where this characteristic will not be a problem. Although the plant is toxic to humans and livestock, it has been used since ancient times in herbal medicines for the treatment of a range of ailments, including elimination of warts, giving rise to several common names. The genus name, Chelidonium, comes from the ancient Greek word χελιδών (chelidṓn) meaning swallow, in the belief that the plant bloomed when the swallows arrived. The specific epithet, majus, is the Latin word meaning greater or larger.
Type: Herbaceous biennial or short lived perennial
Bloom: Loose umbel-like clusters of yellow flowers from late spring through summer
Size: 1-4′ H x .75-18″ W
Light: Part sun to full shade
Soil: Average, medium moist, well-drained
Hardiness: Zones 4-8
Care: Deadhead to extend flowering time
Pests and Diseases: None of significance
Propagation: Seed, division
Companion Plants: Columbine, lobelia, coral bells (Heuchera)
Outstanding Selections: None
Photo Credit: Alvesgaspar Wikimedia Commons
Karen Meyers