Euphorbia platyphyllos or Broad-leaved Spurge is an erect annual native to Europe, but has been naturalized in Southeastern Canada and from Vermont to Missouri in the US. Leaves are dark green, oblanceolate-spatulate to oblong-lanceolate arranged alternately. Leaves can be hairless to lightly hairy. Plants will reach about 30 inches (75 cm) tall. They are very fast growing and make a nice addition to the fall garden or in containers, but they can become very weedy if left unchecked. Plants are hardy in the landscape in USDA zones 2-7.
Blooming: In the greenhouse, plants bloom in the late fall to early winter. The bract leaves of the inflorescence are ovate and the cyathia are 3-5 rayed umbels. Cyathia are bright yellow and very showy.
Culture: Euphorbia platyphyllos needs full sun to partial shade with a well-drained, rich soil mix. In the greenhouse, we use a soil mix consisting of 2 parts peat to 2 parts loam to 1 part sand. Since the plants are fall growing and flowering they are planted in the cool rooms of the greenhouse. Plants are well watered and allowed to dry somewhat before watering again. We fertilize the plants weekly with a balanced fertilizer diluted to 1/2 the strength recommended on the label. We grow the plants until seed is set and the plants are allowed to die off. Seed is collected for use the following fall.
Propagation: Euphorbia platyphyllos is best grown from seed. Seed should be sown in mid- to late-August for best flowering results.
Euphorbia platyphyllos was featured as Plant of the Week December 11-17, 2009.
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Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.