Rough chervil

Chaerophyllum temulum

Rough chervil

Family: Apiaceae

Other Scientific Names:

Chaerophyllum temulentum

Weed class: B
Year Listed: 2022
Native to: Europe, Asia, and North Africa
Is this Weed Toxic?:

Yes, people and animals. It is observed to be toxic to some grazing animals, including horses, cattle, and swine. Sap can cause skin irritation and rashes. Also toxic to people if consumed. See 'Toxicity' section.

Why Is It a Noxious Weed?

Rough chervil creates monocultures in forest areas, disrupting the ecosystem and native speices.

How would I identify it?

General Description

Rough chervil is a biennial, herbaceous plant, covered in rough hairs, grows up to ~ 3.3 feet (1 meter) tall and has clusters of white flowers.

Flower Description

Flowers in compound, somewhat open, umbels of small white flowers, petals 1-3 mm. 

Leaf description

Basal leaves are 2-3 times pinnately compound and hairy on both sides. Leaf segments obtuse or abruptly contract to pointed tip. The compound leaves reduce in size up the stem and are alternately arranged.

Stem description

Stems are solid, have purple spotting or can be fully purple, and are covered in hairs that are somewhat bristly. Stems are swollen below the leaf nodes (where the leaf meet the stems).

Fruit Seed Description

Fruits 4 to 6.5 mm long that gradually taper from the middle to their tip. 4 to 6.5 mm (0.16 to 0.26 inches) long

May Be Confused With

Other members of the carrot/parsley family Apiaceae. Poison hemlock (Conium maculatum) a Class B noxious weed that is deadly toxic, is taller than rough chervil, growing 8-12 feet tall, and also has purple spotted stems but poison hemlock does not have hairs and does not have stem swelling below the leaf nodes.

Wild chervil (Anthriscus sylvestris) is a Class B noxious weed that is not known to be toxic, also grows to about 3 feet tall, but has hollow, ridged, hairy stems without purple spotting.

Wild carrot (Daucus carota) is a Class C noxious weed that grows up to about 4 feet tall, is densely hairy, does not have purple spotting, and the flowers are held in dense, flat-topped compound umbels.

Where does it grow?

Grows in disturbed understories and semi-shaded areas. In areas with moist soils part of the year. Plants have been found primarily in King County, along with herbarium records in Pacific, Grays Harbor, Mason, and Jefferson counties.

How Does it Reproduce?

Plant spread readily by seed.

How Do I Control It?

See the King County Noxious Weed Control Program's control recommendations for rough chervil.

For More Information

King County Noxious Weed Board: rough chervil identification and control

UW Herbarium Image Database information on rough chervil

Calphotos images of rough chervil

King County's report on rough chervil. 

Additional Photos