A Tale of Two Poppies
Compiled by Joyce Tuharsky
Rarely do you find two plants that look so much alike, with similar names, but have such different management concerns. That is the case with two plants commonly known as Celandine.
The Celandine Poppy (Stylophorum diphyllum), also known as the Wood Poppy, is one of our showiest native woodland wildflowers. It is the only member of the Papaveraceae Family that is native to the U.S. Unfortunately, the Celandine Poppy is on the endangered species list in Canada and classified as “imperiled” or “rare” in several U.S. states. Typically found in moist, high-quality forests, it is threatened by the invasion of Garlic Mustard.
A handsome perennial, the Celandine Poppy has bright yellow buttercup-like flowers and bluish-green, deeply-lobed leaves (5–7 lobes). The leaves grow in pairs, up to 6″ long and 2½” across, with a silvery bloom on the underside. The stem is conspicuously hairy. The plant grows 12″–24″ tall. The showy flowers, either solitary or a few clustered in terminal inflorescence, are 1–2″ across, with 4 petals and numerous stamens. The blooming period occurs mid- to late spring and lasts about 2–3 weeks. The flower matures into a nodding, light green, hairy capsule, about 1″ long, and divided into 4 segments. Numerous seeds are released after the capsule splits. Interestingly, these seeds are often dispersed by ants which are attracted to the fleshy, oily appendages on the seeds.
Like other members of this family, the Celandine Poppy contains a yellowish-orange sap which was used by Native Americans for dye and war paint. Be careful though, the sap can be irritating to the skin and eyes; and is toxic to mammals, making this plant deer resistant. The seeds, however, are eaten by snails, slugs, mice, chipmunks, woodchucks, and even deer.
The Celandine Poppy is among the easiest woodland spring wildflowers to cultivate. It is self-sowing and forms natural drifts if the site is right. Sufficient moisture can encourage intermittent blooming throughout the summer. Otherwise, the plant goes dormant during hot, dry weather, but will return in spring.
Be sure not to confuse our native Celandine poppy with the vegetatively similar, but more widespread and invasive Chelidonium majus or Greater Celandine. Most confusedly, this invasive can be found in field books also under the name of “Celandine,” but without the “poppy.” Like our native Stylophorum diphyllum, Chelidonium majus has yellow flowers with 4 petals that bloom in late spring, very similar lobed leaves, yellow sap, and a height of 12″–24″. Its seeds are also dispersed by ants.
It can be tricky to tell these two species apart. The easiest way is by the seed pod. The native Styllophorum has the hanging oval, furry seedpod; while that of the Chelidonium is long and skinny. Other characteristics to note: The flowers of the native (Stylophorum) are bigger (1–2″ across), shinier and decidedly more poppy-like. The flowers of Chelidonium majus are smaller: ¾” across. The leaves of the native plant are a darker blue-green, have fewer but deeper lobes, and grow in opposite pairs. The leaves of the Chelidonium are a lighter yellow-green and attach singly. The buds of the native plant are larger and fewer in a cluster (2–3). The invasive species has smaller buds with more in a cluster (5–6). Styllophorum diphyllum is a perennial; Chelidonium majus is a biennial.
Chelidonium majus was most likely introduced into New England as an herbal remedy for skin diseases. Reported as early as 1672, the plant has since become naturalized and spread across the continent. Chelidonium majus is often found in disturbed areas, especially with moist soil. Very aggressive, it becomes abundant in minimally managed situations, out-competing other plants. Control is mainly via pulling or spraying the plant before seed dispersal.
More information on the native Celandine Poppy (Stylophorum diphyllum) is available at:
https://plants.sc.egov.usda.gov/core/profile?symbol=STDI3
http://www.illinoiswildflowers.info/woodland/plants/cel_poppy.htm
Photos that show comparisons of the leaves, early buds and flowers of the two species are available here: https://bplant.org/compare/586-8527