Hemp Dogbane, Indian Hemp, Amy Root, Prairie Dogbane, Rheumatism Root, Wild Cotton
Plants of the World Online by Kew lists 87 synonyms of this species. You can view the entire list by clicking HERE. I didn’t want to add them all on this page.
Apocynum cannabinum L. is the correct and accepted scientific name for this species. Both 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.
Plants of the World Online by Kew lists 4 species in the genus Apocynum (as of 5-2-21 when I last updated this page). It is a member of the plant family Apocynaceae with 356 genera. Those numbers could change as updates are made.
The above distribution map for Apocynum cannabinum is from Plants of the World Online. Areas in green are where the species is native and purple where it has been introduced. The map from the USDA Plants Database for North America shows the species is native to all 50 states in the U.S. and farther up into Canada.
THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.
I had been out wildflower hunting in the back of the farm on June 19 in 2020, and just over the fence in the main hayfield/pasture I stumbled upon this plant that looked similar to milkweed. Now, I have been back on the family farm since 2013 and I had never seen it before. It was strange how many new wildflowers I observed on the farm since I sold the cows in 2019. Anyway, I took several flowers of this plant and found out it was Apocynum cannabinum. There are several common names including Hemp Dogbane, Indian Hemp, Amy Root, Prairie Dogbane, Rheumatism Root, Wild Cotton, and probably others.
I read a little about this species and found out that all parts are poisonous… The genus name, Apocynum, actually means “poisonous to dogs”… It has been used as a fiber plant and also as a psychoactive drug. Native Americans used to grind the seeds down into a powder and they used the plant to make bows, nets, tie-down straps, fishing lines, and in clothing.
Despite its poisonous properties, Wikipedia has a long list of medicinal uses.
Dogbane Hemp is a perennial species that grows long rhizomes and can produce large colonies. Missouri Plants says they can grow about 3′ tall, but other sites say up to 5 1/2′. All parts secrete a milky sap (latex). Plants will tolerate wet conditions, especially in the spring, as well as being drought tolerant during the hotter months of summer and are found in a variety of habitats with a preference to full sun.
Plants grow from a single stem then start branching out. Stems can be light green to reddish. The stems become somewhat woody toward the base and are hairless (glabrous). The mid to upper portion of the stem and the branches are somewhat pubescent (hairy) or they may be hairless and somewhat chalky (glaucous).
The leaves grow in an opposite manner along the stems and branches. The leaves are normally sessile (with out a petiole), or they may have short petioles. The leaves are referred to as being broadly elliptic-oblong, lanceolate to broadly ovate or elliptic, rounded or shallowly cordate at the base, and taper to a sharp point. The upper surface of the leaves can be light green to yellowish with light green undersides. The leaves are hairless (glabrous)…
The stems and branches terminate with a cluster of flowers.
The small flowers consist of 5 oval white petals, a light green calyx, 5 stamens, and a pistil. The calyces surrounding the flowers have five triangular teeth. The seeds are the same as other milkweed species in the family and are carried by the wind.
The Apocynum cannabinum is easily recognized by its reddish stems. Information online says Apocynum androsaemifolium is similar but has larger flowers with recurved corolla loves and internal pinks stripes.
The Dogbane Hemp produces an abundance of nectar and attracts many types of insects. The good thing is that it is attractive to butterflies and is a larvae host for the AWESOME Snowberry and Hummingbird Clearwing Moths.
You would not want this growing in your garden or fields because it not only grows from spreading roots, it also can reduce corn yields by up to 10% and soybean yields by up to 40%…
I will continue adding more photos as long as I can find them again. Maybe get some better close-ups…
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 100 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 firstname.lastname@example.org. 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)
WORLD FLORA ONLINE (GENUS/SPECIES)
USDA PLANTS DATABASE
USDA PLANT GUIDE
MISSOURI BOTANICAL GARDEN
MISSOURI DEPARTMENT OF CONSERVATION
MSU-MIDWEST WEEDS AND WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
PFAF(PLANTS FOR A FUTURE)
LADY BIRD JOHNSON WILDFLOWER CENTER
FRIENDS OF THE WILDFLOWER GARDEN
NORTH CAROLINA STATE UNIVERSITY
S.W. COLORADO WILDFLOWERS
NOTE: The figures may not match on these websites. It depends on when and how they make updates and when their sources make updates (and if they update their sources or even read what they say). 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. 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 but I do get behind. We are all a work in progress. 🙂