Tall Thoroughwort, Tall Boneset
Synonyms of Eupatorium altissimum: Eupatorium elatum Salisb. Eupatorium floridanum Raf. ex Torr. & A.Gray, Eupatorium ramosum Mill., Eupatorium rupestre Raf., Eupatorium saltuense Fernald, Uncasia altissima Greene
Eupatorium altissimum L. is the correct and accepted scientific name for the Fall Thoroughwort. The species and genus were both named and described by Carl von Linnaeus in the second edition of Species Plantarum in 1753.
According to Plants of the World Online, there are 61 accepted species of Eupatorium (as of 3-18-20 when I am updating this page). Eupatorium is a member of the Asteraceae Family along with 1,760 other genera. Those numbers will change on occasion.
The above map from Plants of the World Online shows the distribution of Eupatorium altissimum. Areas in green are where the plant is native. The map shows no other country where the species is native or has been introduced. The map on the USDA Plants Database for North America is the same.
There are quite a few small colonies of Eupatorium altissimum growing on my farm in Windsor, Missouri in Pettis County (Henry County is across the street). You can find them along back roads, fence rows, and just about anywhere around here.
Eupatorium altissimum is a perennial plant that typically grows to 3-4 feet tall. The hairy stems are unbranched except for the flowering stems on top.
I took several photos while I was working on a friend’s pasture in Johnson County over the summer of 2019. He has several species of wildflowers on his farm I don’t on mine.
The stems can be green or have a purplish tint (Missouri Plants says tan). The fine hairs on the stems give them kind of a powdery appearance.
The top of the flowering stems terminate in kind of a flattish inflorescence with numerous small white flowers. The flowers attract many different insect species. Hopefully, I can get better photos n 2020.
Its dark green leaves grow in an opposite fashion, up to 5” long x 1” wide, and occasionally with teeth along the margins. The leaves are typically lance-shaped, narrowly-ovate and end in a point. Leaves are also covered with fine hairs (pubescent) making them have kind of a coarse texture. Leaves feature a prominent midrib with a lateral vein on each side and several veins running toward the margins.
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. I have grown over 500 different plants and most have pages listed on the right side of the blog. 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 horticulturalist 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.
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