Monday, August 26, 2019

Episode 487 (8-26-19): Calling All Virginia Milkweeds

Click to listen to episode (4:26)

Sections below are the following:
Transcript of Audio
Audio Notes and Acknowledgments
Extra Information
Related Water Radio Episodes
For Virginia Teachers (Relevant SOLs, etc.).

Unless otherwise noted, all Web addresses mentioned were functional as of 8-23-19.


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the week of August 26, 2019.

SOUND – ~ 6 sec

This week, the summertime sounds of Green Frogs and cicadas from a Virginia wetland and meadow set the stage for exploring some silent organisms found in those areas: a group of plants that are part of various natural habitats in the Commonwealth, while also supporting insects that migrate hundreds or thousands of miles annually.  Have a listen for about 20 seconds to several guest voices calling out some common names in this plant group, and see if you know the group.  And here’s a hint: combine the words for a dairy cow’s product and a plant considered out of place.

VOICES - ~20 sec – “Butterfly Weed. Clasping. Common. Few-flower. Four-leaf. Green Comet. Long-leaf. Purple. Red. Swamp. Tall. White. Whorled.”

If you guessed milkweeds, you’re right!  Those were the common names of 13 milkweed species native to Virginia, part of over 100 species native to North America or Central America.  Most species in Virginia are found in meadows, dry forests, pastures, and other relatively dry habitats across the Commonwealth.  But five Virginia species are associated with streamside or wetland habitats; these include the Few-flower, Long-leaf, Purple, Red, and Swamp milkweeds.

Named for their milky sap, milkweeds typically provide large amounts of nectar that attract many insects; one subfamily of butterflies, for example, is commonly known as the milkweed butterflies.  On the other hand, milkweeds contain chemicals that are toxic to some insects and other animals. Both of these aspects of milkweeds contribute to the plants’ well-known association with Monarch Butterflies.  Monarchs—which are noted for their long annual migrations to and from Mexico—depend on various milkweed species as habitat and food for their larvae.  The Monarch also benefits from the toxins in the milkweeds, which render the butterflies distasteful to predators.

In the human realm, some milkweeds have long been used as herbal medicine; for example, both Common Milkweed and Butterfly-weed have been used for lung diseases. That history is reflected in the scientific name of the milkweed genus, Asclepias, which is derived from the name Asklepios, the Greek god of medicine.

Thanks to several Blacksburg friends for lending their voices to this episode.  And in recognition of milkweeds’ connection to Monarchs and other butterflies, we close with part of “The Butterfly,” an adaptation of a traditional Irish tune, by Timothy Seaman of Williamsburg.

MUSIC - ~17 sec - Instrumental


Virginia Water Radio is produced by the Virginia Water Resources Research Center, part of Virginia Tech’s College of Natural Resources and Environment.  For more Virginia water sounds, music, or information, visit us online at, or call the Water Center at (540) 231-5624.  Thanks to Ben Cosgrove for his version of “Shenandoah” to open and close the show.  In Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.


Thanks to neighbors in Blacksburg, Virginia, for recording milkweed common names on August 7, 2019.

The Green Frog and cicada sounds were recorded on August 15, 2015, at a wetland near Toms Creek at Heritage Park in Blacksburg, Va.

“The Butterfly,” from the 2004 CD “Virginia Wildlife,” is copyright by Timothy Seaman and Pine Wind Music, used with permission.  More information about Timothy Seaman is available online at  The “Virginia Wildlife” CD was a collaboration between Mr. Seaman and the Virginia Department of Game and Inland Fisheries to celebrate Virginia’s natural resources and support non-game wildlife programs.

Click here if you’d like to hear the full version (2 min./22 sec.) of the “Shenandoah” arrangement/performance by Ben Cosgrove that opens and closes this episode.  More information about Mr. Cosgrove is available online at


Common Milkweed near Toms Creek in Heritage Park, Blacksburg, Va., July 7, 2019.

Swamp Milkweed in a wetland along the Huckleberry Trail in Montgomery County, Va., July 13, 2019.

Two images above: Monarch Butterfly migration patterns in fall (upper) and spring/summer (lower). Images from the U.S. Forest Service; maps from the U.S. Geological Survey National Atlas; accessed online at


Following are the common and scientific names and typical habitat of species of milkweed native to Virginia and called out in this episode.  All of these are species in the genus Asclepias (abbreviated as “A” in the list below).  The habitat information is quoted from the Alan S. Weakley et al., Flora of Virginia, 2012, (see Sources section below for full details on that reference).

Butterfly Weed, A. tuberosa – Dry woodlands, clearings, fields, pastures, and roadsides. Common throughout [Virginia].”
Clasping Milkweed, A. amplexicaulis – “Dry acidic forests, sandy woodlands, clearings, old fields, and roadsides. Frequent in the Coastal Plain and Piedmont; infrequent in the mountains.”
Common Milkweed, A. syriaca – “Fields, pastures, roadsides, and other open, disturbed habitats. Common throughout [Virginia].”
Few-flower Milkweed, A. lanceolata – “Freshwater to oligohaline [brackish, or slightly salty] tidal marshes; most frequent in wind-tidal marshes of ….far southeastern Virginia. Infrequent in the Coastal Plain.” [For information on wind-tidal marshes, see Virginia Department of Conservation and Recreation, “The Natural Communities of Virginia/Wind-Tidal Oligohaline Marshes,” online at]
Four-leaf Milkweed, A. quadrifolia – “Mesic [moderately moist] to dry forests and woodlands. Frequent on various substrates in the mountains; infrequent and more restricted to base-rich soils in the Piedmont.”
Green [or Green Comet] Milkweed, A. viridiflora – Dry soil of fields, pastures, and roadsides; occasionally in dry rocky woodlands and barrens…. Frequent in the Piedmont and low-elevation mountain valleys; rare elsewhere.”
Long-leaf Milkweed, A. longifolia – “Bogs and sphagnous power-line swales. Rare in the southern Coastal Plain and adjacent outer Piedmont, south of the James River.”
Purple Milkweed, A. purpurascens – “Openings in floodplain forests, wet meadows and clearings, stream banks, upland depression swamps, and clay flatwoods… Infrequent to rare throughout [Virginia].”
Red Milkweed, A. rubra – “Bogs, sphagnous power-line swales, and seeps. Rare in the Coastal Plain and outer Piedmont.”
Swamp Milkweed, A. incarnata – “River and stream shores, wet fields, and meadows. Frequent in the mountains; rare in the Piedmont and Coastal Plain.”
Tall Milkweed, A. exaltata – “Mesic to dry forests, clearings, and meadows; most common in middle to higher elevations. Common in the mountains; rare in the inner Piedmont.”
White Milkweed, A. variegata – Mesic to…dry, upland forests, borders, clearings, and old fields. Frequent in the Coastal Plain and Piedmont; infrequent in mountains.”
Whorled Milkweed, A. verticillata – “Dry woodlands, barrens, clearings, and rock outcrops… Infrequent in the mountains and Piedmont; rare in the Coastal Plain.”


Used for Audio

Biota of North American Program (BONAP), online at

Jason Bittel, “Monarch Butterflies Migrate 3,000 Miles—Here's How,” National Geographic, 10/17/17, online at

Butterflies and Moths of North America, “Family Nymphalidae (Brush-footed Butterflies),” online at  [This family includes 11 subfamilies, one of which is Danainae (Milkweed Butterflies); this site lists 22 species in that subfamily, including the Monarch.]

Rebecca Chandler, “Monarch Lookalikes and How to Tell the Difference,” Save Our Monarchs, 4/17/18, online at

Encyclopedia Britannica, “Asclepiadoideae Plant Subfamily,” online at; and “Milkweed Butterfly,” online at

Alan S. Weakley et al., Flora of Virginia, Foundation of the Flora of Virginia Project, Inc., Richmond, Va., 2012.

Grow Milkweed Plants, “Milkweeds,” online at

Lady Bird Johnson Wildflower Center, “Native Plants Database/Asclepias,” online at

Marion Lois Lobstein, “There and Back Again: A Short Taxonomic History of Milkweed,” Virginia Native Plant Society, undated, online at

George Lohmiller and Becky Lohmiller, “Common Milkweed: Uses and Natural Remedies,” The Old Farmer’s Almanac, 7/8/19, online at

Monarch Watch, online at

Monarch Joint Venture, online at

Monarch Joint Venture and U.S. Forest Service, “Plant Milkweed for Monarchs,” online (as PDF) at

National Wildlife Federation, “Milkweed for Monarchs,” online at

Science Museum Brought to Life, “Asklepios,” online at

Virginia Watson, “Michoacan History,” undated, published by USA Today, online at [Michoacán de Ocampo, in west-central Mexico, is renowned as a winter location for Monarch butterflies.]

U.S. Fish and Wildlife Service, “Five Super Stops on Monarch Migration Trail,” 79/18, online at  [The Eastern Shore of Virginia National Wildlife Refuge is one of stops discussed; information on that refuge is available online at]

U.S. Forest Service, “Monarch Butterfly Migration and Overwintering,” online at

U.S. Forest Service, “Plant of the Week” series:
“Butterfly Milkweed” (Butterfly-weed), by Larry Stritch, undated, online at;
“Common Milkweed,” by David Taylor, undated, online at;
“Green Comet Milkweed,” by David Taylor, undated, online at;
“Purple Milkweed,” by Tania Hanline, undated, online at;
“Swamp Milkweed,” by Forest Russell Holmes, undated, online at

Virginia Native Plant Society/David M. Lawlor, “Imperiled Purple Milkweed at Huntley Meadows Park,” 4/10/16, online at

For More Information about Plants in Virginia and Elsewhere

U.S. Department of Agriculture/Natural Resources Conservation Service, “Plants Data Base,” online at

Virginia Department of Conservation and Recreation/Natural Heritage Division, “Invasive Plant Species of Virginia,” online at

Virginia Department of Game and Inland Fisheries, “Fish and Wildlife Information Service/Monarch Butterfly,” online at

Virginia Native Plant Society, online at  This organization provides information about native species and natural plant habitats. Located at 400 Blandy Farm Lane, Unit #2, Boyce, VA 22620; (540) 837-1600.

Virginia Tech Dendrology, online at  This is the Web site for the dendrology course by Dr. John Seiler in Virginia Tech’s Department of Forest Resources and Environmental Conservation.  The site offers identification keys and fact sheets to trees and other woody plants throughout North America.  This site also information on VTree, a mobile-phone app for tree identification, at


All Water Radio episodes are listed by category at the Index link above (  See particularly the “Insects” and “Plants” subject category.


The episode—the audio, extra information, or sources—may help with the following Virginia Standards of Learning (SOLs).

2013 Music SOLs

SOLs at various grade levels that call for “examining the relationship of music to the other fine arts and other fields of knowledge.”

2010 English SOLs

Reading Theme
6.4 and 7.4 – meanings of unfamiliar words, including word origins and derivations.

2010 Science SOLs

Grades K-6 Earth Resources Theme
4.9 – Va. natural resources, including watersheds, water resources, and organisms.
6.9 – public policy decisions related to the environment (including resource management and conservation, land use decisions, hazard mitigation, cost/benefit assessments).

Grades K-6 Life Processes Theme
K.7 – basic needs and processes of plants and animals.
1.5 – animals’ basic needs and distinguishing characteristics.
2.4 – life cycles.
3.4 – behavioral and physiological adaptations.
4.4 – basic plant anatomy and processes.

Grades K-6 Living Systems Theme
2.5 – living things as part of a system, including habitats.
3.5 – food webs.
3.6 – ecosystems, communities, populations, shared resources.
4.5 – ecosystem interactions and human influences on ecosystems.

Life Science Course
LS.8 – community and population interactions, including food webs, niches, symbiotic relationships.
LS.10 – changes over time in ecosystems, communities, and populations, and factors affecting those changes, including climate changes and catastrophic disturbances.
LS.11 – relationships between ecosystem dynamics and human activity.

Biology Course
BIO.8 – dynamic equilibria and interactions within populations, communities, and ecosystems; including nutrient cycling, succession, effects of natural events and human activities, and analysis of the flora, fauna, and microorganisms of Virginia ecosystems.

Virginia’s SOLs are available from the Virginia Department of Education, online at

Following are links to Water Radio episodes (various topics) designed especially for certain K-12 grade levels.

Episode 250, 1-26-15 – on boiling, for kindergarten through 3rd grade.
Episode 255, 3-2-15 – on density, for 5th and 6th grade.
Episode 282, 9-21-15 – on living vs. non-living, for kindergarten.
Episode 309, 3-28-16 – on temperature regulation in animals, for kindergarten through 12th grade.
Episode 333, 9-12-16 – on dissolved gases, especially dissolved oxygen in aquatic habitats, for 5th grade.
Episode 403, 1-15-18 – on freezing and ice, for kindergarten through 3rd grade.
Episode 404, 1-22-18 – on ice on ponds and lakes, for 4th through 8th grade.
Episode 406, 2-5-18 – on ice on rivers, for middle school.
Episode 407, 2-12-18 – on snow chemistry and physics, for high school.
Episode 483, 7-29-19 – on buoyancy and drag, for middle school and high school.