Late-flowering thoroughwort
Eupatorium serotinum
Bees, wasps, flies, small to medium-sized butterflies, skippers, moths, mosquitoes, and other insects revere late-flowering thoroughwort, Eupatorium serotinum. Also known as late-flowering boneset, this perennial plant is topped by a flat-topped cluster of white flowers (corymb) in the late summer and early fall.
You will find this plant, often unnoticed when not in flower, along roadsides, mosquito control dikes, and perhaps in disturbed places in your own yard. Usually unbranched and growing from three to six feet tall, this plant has opposite lanceolate leaves with decidely toothed margins. Its range is vast and reaches throughout all of Florida west to Texas and north up to on Ontario. In New York, late-flowering thoroughwort is listed as endangered.
The genus name, Eupatorium, honors Mithridates VI Eupator, King of Pontus about 115 BC, who is said to have discovered an antidote to a poison in one of the species in this genus. Its species name, serotinum, means late-flowering.
Flowering gloriously in some of the disturbed areas at the Oslo Riverfront Conservation Area right now, late-flowering thoroughwort is attracting bevies of mangrove buckeye and southern white butterflies for its copious nectar, as well as bunches of bees. Bees both sip its nectar and collect its pollen. Beetles feast on its pollen, too. Late-flowering thoroughwort is an important fall food source for insect-eating birds.
Text & Photos by Janice Broda
