Asclepias speciosa

Secure (NatureServe)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Gentianales
Family: Apocynaceae
Genus: Asclepias
Species:
A. speciosa
Binomial name
Asclepias speciosa
Asclepias speciosa, West Eugene wetlands, Oregon

Asclepias speciosa is a milky-sapped perennial plant in the dogbane family (Apocynaceae), known commonly as the showy milkweed and is found in the western half of North America.[1][2]

Description

This flowering plant is a hairy, erect perennial growing up to 120 cm (47 in) in height.[3] The pointed, elongate, simple, entire leaves are about 10–20 cm (4–8 in) long and arranged oppositely on stalks.[3] Milky sap is released when the leaves or stems are bruised or cut.[4]

The flowers are about 2 cm (3⁄4 in) wide,[3] hirsute, pale pink to pinkish-purple, and occur in dense umbellate cymes. Their corollas are reflexed and the central flower parts, five hoods with prominent hooks, form a star shape. The fruit is a rough follicle about 5–10 cm (2–4 in) long[3] and filled with many flat oval seeds, each with silky hairs.

This species flowers from May through August.[2][3]

Many other species in the genus Asclepias are toxic,[3] particularly to livestock.[5]

Distribution and habitat

This species is native to the western half of North America,[6] including British Columbia and from the Cascade Range in California east to the central United States.[3] It grows along streams, dry slopes, open woodland areas, and roadsides.[4]

Ecology

Asclepias speciosa is a specific monarch butterfly food and habitat plant. Additionally, phenylacetaldehyde produced by the plants attracts Synanthedon myopaeformis, the red-belted clearwing moth.[7] It is also a larval host for the dogbane tiger moth and the queen butterfly.[8]

Monarch Watch provides information on rearing monarchs and their host plants.[9] Efforts to restore falling monarch butterfly populations by establishing butterfly gardens and monarch migratory "waystations" require particular attention to the target species' food preferences and population cycles, as well to the conditions needed to propagate and maintain their food plants.[10]

For example, where it grows in Michigan and surrounding areas and in the western US, monarchs reproduce on A. speciosa, especially when its foliage is soft and fresh. Because monarch reproduction in those areas peaks in late summer when milkweed foliage is old and tough, A. speciosa needs to be mowed or cut back in June or July to assure that it will be regrowing rapidly when monarch reproduction reaches its peak.[11]

The seeds of some milkweeds need periods of cold treatment (cold stratification) before they will germinate.[12] To protect seeds from washing away during heavy rains and from seed–eating birds, one can cover the seeds with a light fabric or with an 13 mm (0.5 in) layer of straw mulch.[13] However, mulch acts as an insulator. Thicker layers of mulch can prevent seeds from germinating if they prevent soil temperatures from rising enough when winter ends. Further, few seedlings can push through a thick layer of mulch.[14]

Uses

Native Americans used fiber in the stems for rope, basketry, and nets.[2] Some Native Americans used the milky sap for medicinal purposes.[2]

Although care is needed to distinguish the species from highly toxic species in the genus,[3] the young leaves and seed pods of A. speciosa can be boiled and eaten.[15]

References

  1. ^ (1) Stevens, Michelle (May 30, 2006). "Plant guide for Asclepias speciosa" (PDF). Washington, D.C.: United States Department of Agriculture: Natural Resources Conservation Service. Archived (PDF) from the original on July 12, 2021. Retrieved July 12, 2021.
    (2) Young-Mathews, A.; Eldredge, E. (2012). "Plant fact sheet for showy milkweed (Asclepias speciosa)" (PDF). United States Department of Agriculture: Natural Resources Conservation Service, Corvallis Plant Materials Center, Oregon, and Great Basin Plant Materials Center, Fallon, Nevada. Archived (PDF) from the original on April 1, 2021. Retrieved July 12, 2021.
    (3) "Asclepias speciosa". Washington, D.C.: United States Department of Agriculture: United States Forest Service. Archived from the original on March 7, 2021. Retrieved July 12, 2021.
  2. ^ a b c d Wiese, Karen (2000). "Showy Milkweed: Asclepias speciosa". Sierra Nevada wildflowers: a field guide to common wildflowers and shrubs of the Sierra Nevada, including Yosemite, Sequoia, and Kings Canyon National Parks. Helena, Montana: Falcon Publishing, Inc. p. 50. ISBN 0585362831. LCCN 00022385. OCLC 47011272. Retrieved July 12, 2021 – via Internet Archive.
  3. ^ a b c d e f g h Spellenberg, Richard (2001) [1979]. National Audubon Society Field Guide to North American Wildflowers: Western Region (rev ed.). Knopf. p. 348. ISBN 978-0-375-40233-3.
  4. ^ a b "Asclepias speciosa - Plant Finder". www.missouribotanicalgarden.org. Retrieved February 16, 2022.
  5. ^ Fagan, Damian (2019). Wildflowers of Oregon: A Field Guide to Over 400 Wildflowers, Trees, and Shrubs of the Coast, Cascades, and High Desert. Guilford, CT: FalconGuides. p. 187. ISBN 978-1-4930-3633-2. OCLC 1073035766.
  6. ^ "Asclepias speciosa Torr.: showy milkweed". Washington, D.C.: United States Department of Agriculture: Natural Resources Conservation Service. Retrieved July 12, 2021.
  7. ^ Eby, Chelsea; Gardiner, Mark G.T.; Gries, Regine; Judd, Gary J.R.; Khaskin, Grigori; Gries, Gerhard (April 1, 2013). "Phenylacetaldehyde attracts male and female apple clearwing moths, Synanthedon myopaeformis, to inflorescences of showy milkweed, Asclepias speciosa". Entomologia Experimentalis et Applicata. 147 (1): 82–92. doi:10.1111/eea.12045. ISSN 1570-7458. S2CID 84552298.
  8. ^ The Xerces Society (2016), Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects, Timber Press.
  9. ^ "Monarch Watch". monarchwatch.org. Retrieved September 27, 2015.
  10. ^ (1) Borders, Brianna; Lee–Mäder, Eric (2014). "Milkweed Propagation and Seed Production" (PDF). Milkweeds: A Conservation Practitioner's Guide: Plant Ecology, Seed Production Methods, and Habitat Restoration Opportunities. Portland, Oregon: The Xerces Society for Invertebrate Conservation. pp. 21–95. Archived (PDF) from the original on July 4, 2021. Retrieved July 12, 2021.
    (2) Landis, Thomas D.; Dumroese, R. Kasten (2015). "Propagating Native Milkweeds for Restoring Monarch Butterfly Habitat" (PDF). International Plant Propagators' Society, Combined Proceedings (2014). 64: 299–307. Archived (PDF) from the original on March 8, 2021. Retrieved July 11, 2021 – via United States Department of Agriculture: United States Forest Service.
  11. ^ National Academies of Sciences, Engineering, and Medicine (2020). Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies. Washington, D.C.: National Academies Press. pp. 79–80. doi:10.17226/25693. ISBN 9780309481328. LCCN 2020935714. OCLC 1229163481. S2CID 218854539. National Cooperative Highway Research Program (NCRHP) Research Report 942. Archived from the original on July 29, 2020. Retrieved July 8, 2021. Could roadside mowing stimulate milkweed growth and support monarch breeding? Limited research in eastern North America has shown that spring or summer mowing can promote new growth and extend the availability of milkweed plants for monarch breeding. Mowing may stimulate growth of some milkweed species, particularly those that spread through rhizomes like common milkweed (A. syriaca) and showy milkweed (A. speciosa). Summer (June or July) mowing in Michigan resulted in more monarch eggs on regenerated stems than unmowed stems. Summer (July) mowing and burning can increase green antelopehorn milkweed (A. viridis) availability in the late summer and early fall in the Southern Great Plains, whereas in areas without mowing, the milkweed has senesced by August. In the West, showy milkweed will regrow after summer mowing and continue to support monarch breeding (Stephanie McKnight, personal observation). However, more research is needed in other areas to determine the optimal timing and frequency of mowing that promotes not only milkweed but also nectar plants. It is also unknown if the benefit of additional milkweed availability in the fall outweighs the costs of the larval mortality caused by summer mowing. The benefits are likely greater in areas that primarily have breeding monarchs in the spring and fall and where the dominant species of milkweed spread by rhizomes. Sources: Alcock et al. 2016; Baum and Mueller, 2015; Bhowick 1994; Haan and Landis 2019; Fischer et al. 2015((cite book)): CS1 maint: multiple names: authors list (link)
  12. ^ (1) Borders, Brianna; Lee–Mäder, Eric (2014). "Milkweed Propagation and Seed Production: Stratification" (PDF). Milkweeds: A Conservation Practitioner's Guide: Plant Ecology, Seed Production Methods, and Habitat Restoration Opportunities. Portland, Oregon: The Xerces Society for Invertebrate Conservation. pp. 28–29. Archived (PDF) from the original on July 4, 2021. Retrieved July 12, 2021.
    (2) Landis, Thomas D.; Dumroese, R. Kasten (2015). "Propagating Native Milkweeds for Restoring Monarch Butterfly Habitat" (PDF). International Plant Propagators' Society, Combined Proceedings (2014). 64: 302. Archived (PDF) from the original on March 8, 2021. Retrieved July 11, 2021 – via United States Department of Agriculture: United States Forest Service. Many sources of milkweed seeds require stratification (cold, moist treatment) before sowing. In a review of stratification requirements for common milkweed, recommendations varied from as short as 7 days to as long as 11 months at 5°C (41°F) (Luna and Dumroese, 2013). Butterfly milkweed (A. tuberosa) germination increased from 29 to 48 to 62% as stratification duration increased from 0 to 30 to 60 days, respectively (Bir, 1986). Our informal natural stratification trial with showy (milkweed) and narrow leaf milkweed (A. fascicularis) in southern Oregon revealed that seeds began to germinate after 15 weeks in stratification (Fig. 3A).
    (3) Higgins, Adrian (May 27, 2015). "7 milkweed varieties and where to find them". Home & Garden. The Washington Post. Archived from the original on September 26, 2020. Retrieved October 17, 2020. Seed may be stubborn to germinate and may need a period of cold treatment..
  13. ^ (1) Mader, Eric; Shepherd, Mathew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen (2011). Attracting Native Pollinators: Protecting North America's Bees and Butterflies: The Xerces Society guide. North Adams, Massachusetts: Storey Publishing. pp. 113–114. ISBN 9781603427470. LCCN 2010043054. OCLC 776997073. Retrieved July 7, 2021 – via Internet Archive.
    (2) Landis, Thomas D.; Dumroese, R. Kasten (2015). "Propagating Native Milkweeds for Restoring Monarch Butterfly Habitat" (PDF). International Plant Propagators' Society, Combined Proceedings (2014). 64: 302. Archived (PDF) from the original on March 8, 2021. Retrieved July 11, 2021 – via United States Department of Agriculture: United States Forest Service. Any of the standard seed propagation methods (Landis et al., 1999) are effective with milkweed. Direct sowing of non-stratified seeds during the fall followed by exposure to ambient winter conditions can be effective, but the seeds must be mulched and protected. Cover sown seeds with a thin mulch; research has found that common milkweed seeds germinated better when planted 1 to 2 cm (0.4 to 0.8 in.) deep than when at the soil surface (Jeffery and Robison, 1971).
  14. ^ Bush-Brown, James; Bush-Brown, Louise (1958). "Chapter 32: Mulches". America's garden book. New York: Charles Scribner's Sons. p. 768. LCCN 58005738. OCLC 597041748 – via Internet Archive.
  15. ^ Lyons, C. P. (1956). Trees, Shrubs and Flowers to Know in Washington (1st ed.). Canada: J. M. Dent & Sons. p. 196.

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