Grasslands and human disturbed areas
Western North America and the American Midwest
No listed status
This species is
to the Truckee Meadows.
Showy milkweed are perennial plants that grow between 1.5 and 3 feet tall. They have opposite leaves with tiny surface hairs and large, tear-drop shaped fruit pods that split to release wind dispersed seeds with long white hairs. Showy milkweed, which is closely related to common milkweed, have small white/pink flowers that grow rounded clusters.
The leaves, stems, and pods of showy milkweed contain a toxic (cardenolides) milky sap that deters herbivores from grazing on the plants!
Showy milkweed pollen is stored in masses that contain millions of pollen grains (pollinium) rather than individual pollen grains, which attach to pollinators and are carried to other milkweed plants.
Milkweeds serve as a host plant for monarch butterflies. Their leaves are a main food source for monarch caterpillars, who also depend on them for shelter, reproduction, and metamorphosis.
The major decline in monarch populations over the past decade is mainly due to the loss of milkweed plants because of urbanization and agriculture, as well as the application of herbicides in croplands, rangelands, and roadsides.
Showy milkweed is a hardy plant that can tolerate slightly saline soils, drought, well-drained soil, seasonal flooding, and some shade.
The Jepson Herbarium, Showy Milkweed, 2013, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=14422
Luna, Tara and Dumroese, R D. 2013. “Monarchs (Danaus plexippus) and milkweeds (Asclepias species): The Current Situation and Methods for Propagating Milkweeds.” Native Plants Journal 14(1):5–15.
Xerces Society for Invertebrate Conservation, California Native Plants: Native Milkweeds, 2011, https://xerces.org/publications/identification-and-monitoring-guides/native-milkweeds-california-pollinator-plants
Borders, B and Mader, E. 2014. “Milkweeds: A Conservation Practitioner’s Guide.” 146 pp. Portland, OR. The Xerces Society for Invertebrate Conservation.
Lady Bird Johnson Wildflower Center, Showy Milkweed, 2021, https://www.wildflower.org/plants/result.php?id_plant=assp
USDA PLANTS Database, Showy Milkweed, 2021, https://plants.usda.gov/core/profile?symbol=ASSP
Image: USFWS Mountain-Prairie, https://www.flickr.com/photos/usfwsmtnprairie/40986027620, license https://creativecommons.org/licenses/by/2.0/, cropped from original.
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