Eupatorium altissimum is a perennial plant whose native range includes much of the eastern United States and Canada. It almost always grows on limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 soils, as does Brickellia

Brickellia

Brickellia is a genus of about 100 species of plants in the sunflower family , known commonly as brickellbushes. They are found in North America, Mexico, and Central America. Many species are native to the American southwest, especially Texas...

 eupatorioides, which it is potentially confused with. It can hybridize with Eupatorium serotinum

Eupatorium serotinum

Eupatorium serotinum, also known as late boneset or late thoroughwort, is a fall-blooming herbaceous plant native to North America...

.

It is part of Eupatorium

Eupatorium

Eupatorium is a genus of flowering plants in the aster family, Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennial plants growing to 0.5–3 m tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere....

even when that genus is defined narrowly, to include about 40 species of mostly white-flowered plants of North America, Asia, and Europe.

External links

• Eupatorium altissimum from missouriplants.com
• PLANTS profile