Stylophorum diphyllum - Wood Poppy

Stylophorum diphyllum ( Wood Poppy )
An excellent moderate to fast spreading, rhizomatous perennial groundcover that can reach up to 24 inches tall and 32 inches wide, though sometimes as much as 32 inches in height and spreading indefinately on ideal sites. Some extremely old colonies in old growth forests possibly dating hundreds of years have been measured up to 50 feet across. The Wood Poppy is however not difficult to contain and is an excellent groundcover for wooded lots and is always a welcome appearance in spring. Personally I really like the foliage and it is one of my favorite perennials thus making "native gardening" a very attractive proposition.
The Wood Poppy is native to rich, mature forest in eastern North America ( from Wisconsin to Traverse City, Michigan to London, Ontario to southwest Pennsylvania; south to northern Arkansas to northern Georgia to Virginia ). It is extinct in the wild in Wisconsin and Pennsylvania. It is close to extinction in Canada due to deforestation in the southern Ontario counties it calls home. One such county where my hometown is within has gone from 97 % tree cover to 3 % between 1870 and 1970 and still remains at about 3 % with agriculture, industry and suburbanisation as well as exotic tree diseases being the culprit. In Canada, it has been federally endangered since 1993. In Ontario, four historic collections are known from the 1880s, all along the Thames River near London, Ontario. Many more colonies may have unknowingly been wiped out in Essex County during the massive scale logging and fires that occured in the 1870 to 1890 period. Further searches should be done in rich woods and floodplain forests. Until rediscovered in 1993 it was presumed extinct from Ontario since 1889. In the USA: THREATENED OR ENDANGERED IN - Alabama, Arkansas, Georgia, northern Michigan, Maryland and Virginia ( natural range in Pennsylvania is uncertain with only unconfirmed reports from Alleghany County )
The downy, pinnately divided, semi-evergreen to deciduous ( depending on climate ) foliage is up to 15 inches in length. The oval leaves are deeply scalloped with incised lobes. The foliage is mid-green. In zone 7 it typically grows from mid April to September.
The brilliant yellow, poppy-like flowers up to 2 inches across are borne in clusters during mid-spring ( March to May depending on climate zone, rarely to mid-summer ). Deadheading may extend the bloom season.
The flowers are followed by silvery seed pods.
The sap on the Wood Poppy is yellow.
A perennial for moist, rich soil with adequate compost in partial shade or shade. Hardy zones 4 to 8. Being that it is so easy to grow one can easily wonder how it can be so rare in the wild that most people never seen a Wood Poppy.
In the upper Midwest, Great Lakes and interior New England; seed sources from Ontario / northern Michigan should be used and I do think horticultural selections should be made from such to take pressure off wild populations. Interestingly most plants sold in nurseries in Ontario originate from non native, less hardy seed stock from the mid southern U.S.
Plants can be cut back after seeds are released for lush new foliage.
Propagation is from seed and it often seeds itself into new places if not deadheaded after flowers ( the plant is so beautiful who would want to stop it from seeding ).

* photos taken on Apr 14 2013 in Columbia, MD

* photo taken on March 28 2010 @ U.S. National Arboretum, D.C.

* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.




* photos taken on June 17 2011 in Columbia, MD

* photo taken on June 23 2013 @ U.S. National Arboretum, Washington, DC

* photos taken on July 10 2013 in Ellicott City, MD

* photos taken on May 1 2014 in Columbia, MD

* photos taken on May 5 2015 in Columbia, MD

* photos taken on May 6 2015 in Ellicott City, MD

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photos taken on Apr 12 2017 in Columbia, MD

* photos taken on Apr 28 2017 in Ellicott City, MD

* photo taken on Apr 20 2018 in Columbia, MD

* photo taken on Apr 24 2019 in Columbia, MD

* photos taken on May 14 2019 in Ellicott City, MD

* photos taken on Apr 2 2020 in Columbia, MD

* photos taken on Apr 14 2020 in Columbia, MD

* photos taken on Apr 10 2023 in Columbia, MD

* photo taken on June 18 2022 in Columbia, MD

Stylophorum lasiocarpum ( Chinese Wood Poppy )
Native to central and eastern China and reaching up to 2 feet in height and width; this Wood Poppy is very similar to related Stylophorum diphyllum. The foliage is slightly longer, up to 18 inches in length. The foliage is mid-green.
Unlike its North American cousin; its flowers ( also up to 2 inches wide ) are yellow-orange and its sap is red.
Hardy zones 4 to 8. With moist soil; the Chinese Wood Poppy is heat tolerant and its foliage is also frost resistant.