Plant Image
Aspen Creek Tr - Sue Smith

Yavapai County Native & Naturalized Plants

Conyza canadensis - Canadian horseweed

Other Common Names: horseweed
Plant Form: Forb or Subshrub

Family: Asteraceae

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Aspen Creek Tr
Sue Smith
Flower head
Aspen Creek Tr
Sue Smith
Aspen Creek Tr
Sue Smith
Leaf attachment
Aspen Creek Tr
Sue Smith
Plant - summer
Aspen Creek Tr
Sue Smith
Young plant - summer
Aspen Creek Tr
Sue Smith
Forb Plant Description

Origin: Introduced   Life Cycle: Biennial or annual
General Desc: A common very vertical, tall weed. Not branched except for multiple flowering stems spreading outward near the top of the plant. Considered invasive in some areas of the U.S. Heights reported as much as 7 feet.
Identification notes: Tall annual herb, many branched leafy stems with alternate simple leaves. Stem and branches covered with short, bristly hairs. Flower heads 3 to 5 mm across, crowded in branched terminal clusters, composed of white ray and yellow disc florets.
Height: Up to 7 feet


Habitat Description: Found in pastures, fields, waste areas and along roadsides. Grows in many different soils.
Plant Communities: Disturbed Areas
Elevation: 1000 - 8000 feet

Flower Characteristics

Color: White and yellow     Shape: Daisy or dandelion-like in clusters     Tubular: N     Flowering Period: Jul - Oct
Description: Has many inconspicuous flowers forming small composite flower heads about 1/8 inch across. Composite heads have white ray flowers and yellow disc flowers.

Leaf and Stem Characteristics

Leaf Color: Green     Leaf Type: Simple     Leaf Shape: Narrow     Leaf Margin: Smooth     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: Leaves and stems     Spines: N
Leaf Description: Leaves alternate around the main vertical stem. To 4 inches long and 1/2 inch wide. Has a few white hairs along the edge.

Fruit and Seed Characteristics

Fruit Color: Brown   
Fruit Type: Achene
Fruit Notes: Elliptic in shape.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
Last Updated: Nov 21, 2021
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