COUNTY AG NEWS

Wild Parsnip: What is it and why should we be concerned about it?

Wild Parsnip, Pastinaca sativa, is an invasive member of the carrot family that continues to spread into unmanaged areas throughout Wisconsin. It likes to grow in sunny, grassy areas along roadsides, railroads, and field borders, but it is not limited to these conditions. Primary means of spread is by seed that can be moved long distances while mowing roadsides after the plant has set seed. The biggest concern isn’t the fact that it is invasive and rapidly spreading but that it will cause burns and blistering of the skin if you come in contact with plant sap in the presence of sunlight. This is known as phytophotodermatitis. Blisters and rashes appear 24 to 48 hours after exposure. Blisters do not spread like poison ivy but are uncomfortable and may leave scars lasting for several months to two years. The plant is a monocarpic (the plant dies after blooming) perennial and has two growth stages. The first year it produces a non-flowering leafy rosette of pinnately compound leaves with 5 to 15 leaflets. It looks a lot like celery at this stage. In the second to third year, it produces a flowering stem four to five feet tall. Stems are grooved, hollow, and have alternately arranged compound leaves with 2 – 5 pairs of opposite, sharply toothed leaflets and petioles that wrap around the stems. Flowers are flat-topped clusters (umbels) of yellow flowers 2 – 6 inches wide, blooming in late spring to mid-summer in Wisc === onsin. Seeds begin to form mid to late July, changing from yellow-green to tan as they mature. Along with the seeds maturing, the stems and leaves begin to senesce, turning tan to brown in color. 

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