Plant Image
Granite Mtn - Tr 308 - SS

Yavapai County Native & Naturalized Plants

Asclepias asperula - spider milkweed

Synonyms: Asclepais caparicornu
Other Common Names: antelope horns
Plant Form: Forb

Family: Asclepiadaceae

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Willow Dells Tr
Granite Mtn - Tr 308
Granite Mtn - Tr 308
Plant - spring
Willow Dells Tr
Plant with seed pods
Granite Mtn - Tr 308
Willow Dells Tr
Forb Plant Description

Origin: Native   Life Cycle: Perennial
General Desc: A clump-forming, 1 to 2 foot perennial with an upright or sprawling habit. The stems are densely covered with minute hairs. Milkweeds are the primary food source for Monarch caterpillars.
Height: 1 to 2 feet.


Habitat Description: Dry plains, slopes, and clearings in oak woodlands and pine forests.
Plant Communities: Interior Chaparral, Semidesert Grasslands, Pinyon Juniper Woodland, Montane Conifer Forest
Elevation: 3000 - 9000 feet

Flower Characteristics

Color: Greenish-white     Shape: Irregular in round clusters     Tubular: N     Flowering Period: Apr - Aug
Description: Greenish-white with purple tinges; fragrant; to 1/2 inch wide. Flower has five upward-curving petals and a five-part crown of purple horns tipped with white. Flowers form clusters 3–4 inches wide at the end of the flower stem.

Leaf and Stem Characteristics

Leaf Color: Dark green     Leaf Type: Simple     Leaf Shape: Triangular     Leaf Margin: Smooth     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: Stems     Spines: N
Leaf Description: Narrow, 4 to 8 inches long, with grayish stripe down mid-vein and pointed tips and wavy edges that curl upward. The long, thick, narrow leaves are often folded lengthwise.

Fruit and Seed Characteristics

Fruit Color: Green   
Fruit Type: Pod
Fruit Notes: Stout, 6 inches long, green pod with olive-green and pink streaks. Pod has lengthwise wrinkles and a pointed tip. As they grow and begin to curve, they resemble antelope horns.
Seed Notes: Pod contains flat brown seeds.

  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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