Also called pig-potato and stiff cowbane, this herbaceous perennial is in the parsley family, Apiaceae, that also includes celery, Queen Anne’s lace, and poison hemlock. It is native to eastern US from New York south to Florida and west to Texas and Minnesota where it grows in wet areas such as bogs, seeps, marshes, swamp, fens, wet prairies, and streambanks. Plants grow 2-6′ tall from a fleshy rootsystem and have sparingly branched, medium green stems with conspicuous veining. The medium green compound leaves are up to 12′ long and have 5 to 11 leaflets 1.5- 4″ long. Flat umbels 3-6″ across appear from late summer to fall and are comprised of 10-25 umbellets with up to 25 flowers each. Each flower is 1/8″ across and has 5 white spreading petals. Both foliage and roots are toxic to mammals. The genus name, Oxypolis, comes from the Greek words oxus meaning sharp and referring the awl-shaped secondary bracts, and polios meaning white an referring to the petals of the flowers. The specific epithet, rigidior, is the Latin word meaning stiffer.
Type: Herbaceous perennial
Bloom:Compound flat umbels 3-6″ of white flowers from late summer to fall
Size: 2-6′ H
Light: Full to partial sun
Soil: Average, wet to moist
Hardiness: Zones 4-8
Care: Low maintenance
Pests and Diseases: None of significance
Propagation: Seed, division
Companion Plants: Swamp goldenrod, rosepink, wild mint
Photo Credit: Wikipedia