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NPIN: Native Plant Database

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Asclepias speciosa (Showy milkweed)
Cliffe, Harry

Asclepias speciosa

Asclepias speciosa Torr.

Showy milkweed

Asclepiadaceae (Milkweed Family)

Synonym(s): Asclepias giffordii

USDA Symbol: assp

USDA Native Status: L48 (N), CAN (N)

A stout, sparingly branched, pubescent perennial, 1 1/2-3 ft. tall, with large, oval, blue-green leaves and showy, spherical clusters of rose-colored flowers. Flowers occur at the top of the stem and on stalks from leaf axils. A grayish, velvety plant with erect leafy stems and with umbels of star-like pinkish flowers in upper axils and at top. Sap milky.

This species is closely related to the Common milkweed, A. syriaca, with which it sometimes hybridizes at the eastern limits of its distribution. These species are similar in appearance and growth form (tall and robust), but can be distinguished by the layer of fine white hairs on A. speciosa and flowers that look like small crowns. Unlike A. syriaca, A. speciosa does not form large clones.

 

Plant Characteristics

Duration: Perennial
Habit: Herb
Root Type: Tap
Leaf Arrangement: Opposite
Leaf Complexity: Simple
Leaf Shape: Ovate
Leaf Venation: Pinnate
Leaf Margin: Entire
Fruit Type: Follicle
Size Notes: Generally 1 ½ – 3 ft (½ – 1 m) but can reach 6 ft ( 1.8 m) under favorable conditions.
Leaf: Blue-green color, course, and hairy. Leaf arrangement is opposite and attachment is petiolate. Leaf petioles are 1/8-3/8 in (4-10mm) long. Stems stand erect. Oval shaped, 3-8 in (7 ½ – 20 cm) long and 1-4 in (2 ½-10 cm) wide.
Fruit: Pods 3-4 in (7 ½-10 cm) long. Erect, with hair covering entire pod.
Size Class: 1-3 ft. , 3-6 ft.

Bloom Information

Bloom Color: Pink , Green , Purple
Bloom Time: May , Jun , Jul , Aug , Sep

Distribution

USA: AZ , CA , CO , IA , ID , IL , KS , MI , MN , MT , ND , NE , NM , NV , OK , OR , SD , TX , UT , WA , WI , WY
Canada: AB , SK
Native Distribution: S. Man. & w. MN to B.C., s. to TX & CA
Native Habitat: Found in habitats ranging from sunny and dry to moist in savannahs, prairies, road-sides, old fields, and meadows.

Growing Conditions

Water Use: Medium
Light Requirement: Sun
Soil Moisture: Moist
CaCO3 Tolerance: Medium
Soil Description: Can grow in course, medium, and fine soils.
Conditions Comments: Not shade tolerant. Must be in open spaces.

Benefit

Use Wildlife: Hummingbirds.
Use Other: The fibers from this plant were used by Native Americans to make ropes, nets and other items.
Warning: This is one of the least toxic of the milkweeds. There are even recipes for preparing this species as a vegetable, but the plants should be positively identified as some of the milkweeds are highly poisonous, and eating them can result in death.
Conspicuous Flowers: yes
Fragrant Flowers: yes
Attracts: Butterflies , Hummingbirds
Larval Host: Monarch

Value to Beneficial Insects

Special Value to Native Bees
Special Value to Bumble Bees
Special Value to Honey Bees
Supports Conservation Biological Control

This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.

Butterflies and Moths of North America (BAMONA)

Asclepias speciosa is a larval host and/or nectar source for:
Monarch
(Danaus plexippus)

Larval Host
Learn more at BAMONA

Propagation

Propagation Material: Seeds
Description: Root cuttings can be taken in fall or early spring. Seeds may be sown outside in late fall or the following spring. Germination of spring-planted seeds is enhanced by moist stratification.
Seed Treatment: Stratify 3 months at 40 degrees.
Commercially Avail: yes

Find Seed or Plants

Order seed of this species from Native American Seed and help support the Wildflower Center.

Find seed sources for this species at the Native Seed Network.

National Wetland Indicator Status

Region:AGCPAKAWCBEMPGPHIMWNCNEWMVE
Status: FAC FAC FAC FAC FAC FAC
This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Suppliers Directory

According to the inventory provided by Associate Suppliers, this plant is available at the following locations:

Oregon Native Plant Nursery - Woodburn, OR

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Santa Barbara Botanic Garden - Santa Barbara, CA
Native Seed Network - Corvallis, OR

Web Reference

Webref 20 - Milkweed Profiles (0) Monarch Watch

Additional resources

USDA: Find Asclepias speciosa in USDA Plants
FNA: Find Asclepias speciosa in the Flora of North America (if available)
Google: Search Google for Asclepias speciosa

Metadata

Record Modified: 2014-11-12
Research By: TWC Staff

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