Plant Image
Granite Mtn - Tr 308 - Sue Smith

Yavapai County Native & Naturalized Plants

Asclepias asperula - spider milkweed

Other Common Names: antelope horns, antelopehorn milkweed
Plant Form: Forb

Family: Asclepiadaceae

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

Origin: Native   Life Cycle: Perennial
General Desc: A clump-forming plant with an upright or sprawling habit. The stems are densely covered with minute hairs. Milkweeds are the primary food source for Monarch caterpillars.
Identification notes: Several stemmed perennial; woody rhizome; leaves alternate, narrow, tapering, ascending; flowers in large head-like clusters, individual flowers bowl-shaped, 5 greenish-white petals with horn-like purplish appendages (hoods), petals erect in full flower.
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: Regular in round clusters     Tubular: N     Flowering Period: Apr - Aug
Description: Rounded 3 to 4 inches wide clusters of fragrant greenish-white flowers that are to 1/2 inch wide, 5-parted and include sepals, petals, a (corona) arising from the middle of the petals, upright hoods that look like petals and purplish horns.

Leaf and Stem Characteristics

Leaf Color: Dark green     Leaf Type: Simple     Leaf Shape: Narrow     Leaf Margin: Smooth     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: Stems     Spines: N
Leaf Description: Narrow, 4 to 8 inches long with a grayish mid-vein, 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 7.0  
Last Updated: May 10, 2017  
Content Questions/Comments: Email Jeff Schalau  
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