Plant Image
Flower head
Watson woods - Sue Smith

Yavapai County Native & Naturalized Plants

Conium maculatum - poison hemlock

Other Common Names: winter fern
Plant Form: Forb

Family: Apiaceae

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Flower head
Watson woods
Sue Smith
Flower head
Watson woods
Sue Smith
Watson woods
Sue Smith
Plant - summer
Watson woods
Sue Smith
Forb Plant Description

Origin: Introduced   Life Cycle: Biennial
General Desc: Poison hemlock is a tall, erect, branching plant. All parts of the plant are extremely poisonous.
Identification notes: Tall, hairless biennial; stems streaked or spotted with purple blotches; large taproot; pungent odor; leaves pinnately compound, finely divided, and sometimes toothed; flower loose inflorescence of umbels; white.
Height: To 10 feet


Habitat Description: Moist ground near streams and disturbed areas.
Plant Communities: Riparian, Disturbed Areas
Elevation: 5000 - 7500 feet

Flower Characteristics

Color: White     Shape: Regular in round clusters     Tubular: N     Flowering Period: May - Aug
Description: Small white flowers are 5-petaled to 1/8 inch wide. The flowers form small clusters to 1/2 inch wide. The clusters are grouped in compound umbels to 4 inches wide.

Leaf and Stem Characteristics

Leaf Color: Green     Leaf Type: Compound     Leaf Shape: Pinnatifid     Leaf Margin: Lobed     Leaf Attachment: Opposite     Leaves Clasp: N
Hairs: No     Spines: N
Leaf Description: Trianular-shaped leaves are fern-like and finely divided to 2 feet long. Purple-spotted grayish-green stems are hollow.

Fruit and Seed Characteristics

Fruit Color: Light brown   
Fruit Type: Capsule
Fruit Notes: Ovate, 1/8 inch wide.
Seed Notes: Seed face is grooved.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 7.0  
Last Updated: May 10, 2017  
Content Questions/Comments: Email Jeff Schalau  
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