Asclepias syriaca (Common Milkweed) on 6-26-22, #896-5.

Common Milkweed, Butterfly Flower, Silkweed, Virginia Silkweed

Asclepias syriaca

ass-KLE-pee-us  seer-ee-AK-uh

Synonyms of Asclepias syriaca (15) (Updated on 11-17-23 from Plants of the World Online): Asclepias apocinum Gaterau, Asclepias consanguinea Kunze, Asclepias cornuti Decne., Asclepias fragrans Raf., Asclepias globosa Stokes, Asclepias grandifolia Bertol., Asclepias illinoensis Michx. ex Steud., Asclepias intermedia Vail, Asclepias obtusifolia Kunze, Asclepias pubescens Moench, Asclepias pubigera Dumort., Asclepias serica Raf., Asclepias syriaca f. inermis J.R.Churchill, Asclepias syriaca f. leucantha Dore, Asclepias syriaca f. polyphylla B.Boivin

Asclepias syriaca L. is the accepted scientific name for this species of Milkweed. The genus and species were named and described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

As of 11-17-23 when this page was last updated, Plants of the World Online by Kew lists 204 species in the Asclepias genus. It is a member of the plant family Apocynaceae with 376 genera. Those numbers could change as updates are made on POWO.

The above distribution map for Asclepias syriaca is from Plants of the World Online. Areas in green are where the species is native and purple is where it has been introduced. The map on the USDA Plants Database for North America is similar.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist and continually updated as members post new observations. I post all my observations on iNaturalist. It is very addictive!

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.

When I moved back to the family farm in 2013 and through 2018, there weren’t that many Asclepias syriaca (Common Milkweed) here. There were a few in the main hayfield/pasture and several growing next to the lagoon. Since then they have become abundant… There were several large colonies in 2023.

The Asclepias syriaca is a native perennial wildflower that grows to around 4-6’ tall with deep rhizomes throughout its range. Plants prefer growing in full sun in prairies, pastures, along roadsides, open woods, and waste ground. They are very tough and can grow in a variety of conditions and can grow into large colonies.

Besides milkweeds being host plants for Monarch Butterfly caterpillars, they are beneficial to many other insects as well. Most of the time when I am photographing, there are multiple species of butterflies and other insects feeding on the nectar and on the leaves. They are either feeding or being fed on…

The stout stems are densely hairy (densely pubescent) but sometimes hairless (glabrous). They are usually unbranched below the inflorescence (flower stems). The above photo shows the stems with fine hairs giving it a chalky appearance.

The leaves grow in an opposite manner along the stems and are up to 8” long x 3 1/2” wide. Leaves are described as being broad, oblong or elliptic-ovate, rounded or pointed at the tip. The midribs are usually purplish toward the base. The upper surface is usually hairless but can have very fine, short hairs. The undersides of the leaves usually have very fine, short hairs…

As with all milkweeds, their stems and leaves contain a milky sap that has variable toxicity in the form of cardiac glycosides. The above photo was taken on a friends farm in 2019 after a cow did a little snacking…

Typical of Milkweeds, the flowers grow in globose umbels, 2-10 per stem, emerging from the axils of the upper leaves. The umbels contain 20-100 flowers.

Flowers are about 1/4” across, with 5 reflexed calyx lobes, 5 reflexed corolla lobes (petals), 5 raised hoods with curved horns… Peduncles and pedicels are densely pubescent. Peduncles are the stems between the leaf axils and umbel, while pedicels attach the flowers to the peduncles…

Asclepias syriaca have fruits and seed pods similar to other Milkweeds except that they are covered with narrow warty tubercles…  

The seeds are dispersed through the wind…

If you enjoy photographing and identifying butterflies and insects, milkweeds are a great place to start. There are usually several species of butterflies, bees, beetles, and other odd critters on the flowers, leaves, and stems.

There are A LOT more photos below the links for further, including a few insects feeding…

I found a good write-up called, “The Story of an Organism: Common Milkweed” by Craig Holdrege from The Nature Institute. You Can read it by clicking HERE… It’s quite a story that leaves nothing out about Milkweeds.

I live on a small farm in Windsor, Missouri where I enjoy gardening, collecting plants, and identifying wildflowers. The farm is in Pettis County but Henry County is across the street, and Benton and Johnson aren’t far away. I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
USDA PLANT GUIDE
DAVE’S GARDEN
MISSOURI PLANTS
MISSOURI BOTANICAL GARDEN
MSU-MIDWEST WEEDS AND WILDFLOWERS
MISSOURI DEPARTMENT OF CONSERVATION
iNATURALIST
WILDFLOWERSEARCH
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
NORTH CAROLINA STATE UNIVERSITY
PFAF(PLANTS FOR A FUTURE)
GO BOTANY
LADY BIRD JOHNSON WILDFLOWER CENTER
FLORA FINDER
FRIENDS OF THE WILDFLOWER GARDEN
GARDENIA
U.S. FOREST SERVICE
MONARCH WATCH

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is the most reliable and up-to-date plant database and they make updates on a regular basis. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂

PHOTOS FROM 2022…

The above photo and next 9 were taken on a friend’s farm on July 12, 2019.

 

I took A LOT of photos

 

 

 

The veins of the leaves grow outward from the midrib toward the leaf margins.

View from the top showing the opposite arrangement of the leaves.

The rest of the photos were taken on the farm where I live… There is a good-sized patch next to the lagoon and surrounding area. They are also scattered along the south side of the farm from one end to the other and along the street in front of the pasture.

The Asclepias syriaca has been growing on the bank of the lagoon for several years. Now they are growing in the fence row and pasture in front of it. Even though I mow around the lagoon every week during the summer, I haven’t photographed their flowers…

Unlike most other Milkweeds, Asclepias syriaca has these distinct seed pods with tubercles…

Hmmm… Apparently, aphids also like milkweeds…

<<<<2020>>>>

Starting to bud…

 

 

No matter when it is, the Milkweeds always have insects of some kind somewhere on the plants…

 

 

<<<<2021>>>>

The above photo is of a colony of Asclepias syriaca in the southeast pasture.

The above photo and the next four were taken of a small colony along the fence outside of the front pasture.

 

These plants by the fence flowered earlier than the rest of the plants on my farm…

 

The above and below photos are of the same plant along the south hayfield.

A research team from the biology department at Augustana University in Sioux Falls, South Dakota asked if I would participate in their Milkweed research. Of course, I agreed. The green seedpod of this plant in the south hayfield was one of two I sent once it was dried (but not open).

Once the hay was cut, the Asclepias syriaca wasted no time growing again. Unfortunately, they were not able to flower…

One of these seedpods from a plant growing in the fence along the front pasture was also sent to the research team.

<<<<2022>>>

The photos from June 12 in 2022 were taken next to the road along the south side of Farrington Park in Windsor, MO.

 

 

Photos from June 26 in 2022 were taken on the farm where I live.

Asclepias syriaca (Common Milkweed) on 6-26-22, #896-6.

 

I think the insect above us a Chauliognathus marginatus (Margined Leatherwing Beetle) but it could be ins cousin Chauliognathus pensylvanicus (Goldenrod Soldier Beetle)…

 

 

<<<<2023>>>>