Herbaceous plant that establishes as a rosette with upright leaves persisting for at least one year. Plants flower in subsequent years (typically 2nd or 3rd year), but after plants flower, they die (monocarpic perennial). Flowering stems are stout, hallow, grooved, and up to 5′ tall.
CAUTION: Sap contact with skin in the presence of sunlight can cause a rash that often leads to blisters and discoloration of the skin (phytophotodermatitis). Wear gloves, long sleeves, and pants when handling.
Legal classification in WI: Restricted. The garden parsnip vegetable is the same species as the invasive form. The garden form is not restricted in Wisconsin.
Leaves: Rosette leaves are pinnately compound with 5–15 broad, ovate to oblong leaflets. Stem leaves are alternate, with 2–5 pairs of opposite, sharply toothed leaflets. Petioles wrap around the stem. Upper stem leaves are reduced to narrow bracts.
Flowers: Late spring to midsummer. Numerous, small, five-petaled, yellow flowers in flat umbels 2-6″ wide at the tops of stems and branches.
Fruits and seeds: Seeds are approximately 0.25” in diameter, flat, round, yellowish, and slightly ribbed.
Roots: Deep taproot.
Similar species: Wild parsnip is distinguished from other species in the parsley family by its yellow flowers and pinnately compound leaves which are divided once into more than 5 leaflets. Golden alexander (Zizia aurea; native) can be distinguished from parsnip by its earlier flowering time, shorter stature, less open appearance, and 2-3 pairs of leaflets. Prairie parsley (Polytaenia nuttallii; native) can be distinguished from parsnip by its oblong leaflets with few teeth and rounded umbels.
• Invades prairies, oak savannas, fens, old fields, pastures, and roadsides.
• Thrives in disturbed habitats and along edges of many habitat types.
• Can invade undisturbed grasslands.
• Seeds are readily transported by water.
For more information visit: http://dnr.wi.gov/topic/Invasives/fact/WildParsnip.html
(Photo source http://www.luontoportti.com)