Appearance

Growth form

A biennial or short-lived perennial, usually about 2–5 ft (0.6–1.5 m) tall, with hollow, ribbed green stems that have a fringe of hairs at the joints.

Leaves

Dark green, finely divided, fern-like leaves with sharply pointed segments.

Flowers

Many small white five-petaled flowers in umbrella-shaped clusters, made up of smaller sub-clusters.

Flowering time

April to May in western Washington, setting seed from early May.

Fruit

The narrow, shiny, dark fruits split into pairs of seeds, each with a small point at the top.

Look-alikes

Where it lives

Typical habitats

• Roadsides
• Degraded fields
• Forest edges
• Open woodlands

Range

Native to Europe, western Asia, and northwestern Africa. It was likely brought to North America in seed mixes and is now invasive in many areas of the U.S., including Washington State and the Northeast.

Preferred conditions

Grows in almost any soil and tolerates part shade, so it can spread into forest understories as well as sunny fields.

Flowering

Flowers Apr–May

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Flowers

Flowers Apr–May

Growing it

Propagation

Spreads by seed, which can survive 1–2 years in soil, and by buds on its thick, carrot-like root that can grow into new plants.

Toxicity

The sap can irritate skin, so gloves and long sleeves are advised when pulling it. Because it closely resembles poison hemlock, foraging it is discouraged.

Conservation

IUCN Red List

NENot Evaluated·Not yet assessed

Status

A Class B noxious weed in Washington since 1989, where buying or selling it is illegal; its sale is also banned in Massachusetts, and Vermont lists it on its invasive watch list.

Threats

In Washington State it forms dense patches that crowd out native plants, makes poor forage or hay, and can carry a virus that attacks cultivated carrots, parsnips, and celery.