Plant Image
Granite Mtn - Tr 308 - SS

Yavapai County Native & Naturalized Plants

Asclepias subverticillata - horsetail milkweed

Other Common Names: poison milkweed
Plant Form: Forb

Family: Asclepiadaceae

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Sepals and seed pods
Granite Mtn - Tr 308
Granite Mtn - Tr 308
Granite Mtn - Tr 308
Plant - summer
Willow Dells Tr
Plant - summer
Granite Mtn - Tr 308
Commerce Dr, Prescott
Forb Plant Description

Origin: Native   Life Cycle: Perennial
General Desc: A very abundant plant in Northern Arizona. Stems contain a white sap poisonous to livestock and its dried leaves accidentally bound in hay bales can be lethal. Queen and Monarch butterfly caterpillars eat the toxic leaves with no ill effect.
Height: 1-1/2 to 4 feet


Habitat Description: Grasslands and montane; among grasses, sandy or rocky flats, slopes, roadsides, along trails.
Plant Communities: Interior Chaparral, Semidesert Grasslands, Pinyon Juniper Woodland, Montane Conifer Forest, Disturbed Areas
Elevation: 3000 - 8000 feet

Flower Characteristics

Color: White to greenish white     Shape: Irregular in round clusters     Tubular: N     Flowering Period: May - Sep
Description: Rounded, flat cluster, 1 to 2 inches wide, of many small, odd-shaped flowers, 1/2 inch wide. Flower has 5 lower petals in a flat ring and 5 smaller upper petals raised above.

Leaf and Stem Characteristics

Leaf Color: Dark green     Leaf Type: Simple     Leaf Shape: Other     Leaf Margin: Smooth     Leaf Attachment: Whorl     Leaves Clasp: N
Hairs: No     Spines: N
Leaf Description: Thread-like leaves, 5 inches long, with rolled edges; in whorls of 3 to 5 leaves at stem joints.

Fruit and Seed Characteristics

Fruit Color: brown   
Fruit Type: Pod
Fruit Notes: Erect, slender flattened pod, 4 inches long.
Seed Notes: Each brown seed has a tuft of silky hairs.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 3.1  
Last Updated: June 15, 2013  
Content Questions/Comments: Email Jeff Schalau  
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