Poison Hemlock

Poison Hemlock and Wild Parsnip are Bolting and Blooming

Poison hemlock (Conium maculatum) is one of the deadliest plants in North America. Wild parsnip (Pastinaca sativa) sap can produce severe, painful skin blistering. Both are commonly found growing together in Ohio and both are beginning to bloom meaning the clock is quickly winding down for controlling these non-native nasties.
Published on
Authors
Joe Boggs
The Rise of Poison Hemlock
boggs.47@osu.edu Mon, 03/16/2020 - 15:46
Poison hemlock is a non-native biennial weed that spends its first year as a low-growing basal rosette; the stage that is currently very apparent. Targeting this stage for control will eliminate the first-year rosettes and prevent the development of the towering flowering stage.
Published on
Authors
Joe Boggs
Poison Hemlock and Wild Parsnip are going to Seed in Southern Ohio
boggs.47@osu.edu Fri, 06/21/2019 - 09:09
Poison hemlock and wild parsnip are two of our nastiest non-native weeds found in Ohio. Poison hemlock can kill you while wild parsnip may make you wish you were dead. Both are commonly found growing together and continuously wet conditions caused both to flourish this growing season. The size of some infestations has been remarkable. Poison hemlock produces white flowers on stalks that create a more rounded look; perhaps a bit more like an umbrella.  Wild parsnip has intense yellow flowers with the stalks producing a more flat-topped appearance.
Published on
Authors
Joe Boggs
Erik Draper

Be Alert to Wild Parsnip!

Second-year wild parsnip plants are producing deeply grooved flower stalks topped by characteristic bright yellow blooms in southern Ohio. Landscape managers and gardeners should exercise extreme caution around this non-native invasive biennial plant.
Published on
Authors
Joe Boggs

Be Alert to Poison Hemlock

Poison hemlock is a non-native biennial weed that spends its first year as a low-growing basal rosette; the stage that is currently very apparent. During its second year, plants produce erect, towering stalks and multi-branched stems topped with umbrella-like flowers. Mature plants can measure 6-10' tall and are prolific seed producers.
Published on
Authors
Joe Boggs

Focus on Poison Hemlock Control

Poison Hemlock (Conium maculatum) is one of the deadliest plants in North America. This non-native invasive was imported as an ornamental in the late 1800s from Europe, West Asia, and North Africa. The plant contains highly toxic piperidine alkaloid compounds, including coniine and gamma-coniceine, which cause respiratory failure and death in mammals.
Hort Shorts
Published on
Authors
Joe Boggs

Poison Hemlock Going to Seed

Poison Hemlock Seed

Poison hemlock (Conium maculatum) is among the most deadly plants in North America.  This non-native invasive weed contains highly toxic piperidine alkaloid compounds, including coniine and gamma-coniceine, which cause respiratory failure and death when ingested by mammals.

 

TOXICITY:

Poison hemlock is native to North Africa and Eurasia including Greece.  It's the plant behind Socrates' famous last words, "I drank what?"  Or, maybe it was, "don't try this at home."  Just kidding.  In fact, it was the plant used to poison...

Hort Shorts
Published on
Authors
Joe Boggs
Subscribe to Poison Hemlock