Eupatorium rugosum

White Snakeroot — Eupatorium rugosum or Ageratina altissima


  • date: Sept 13, 2014
  • location: Columbus, OH, woods between Olentangy trail and mountain biking hills where Duncan dead-ends
  • overall habitat: mixed mesophytic forest
  • microhabitat: damp soil or clay
  • Family: Asteraceae

This tall (1-5′) plant has tooted opposite ovate (egg-shaped) leaves that come to a sharp point. It has flowers in many clusters on its end tips, and on the tips ofstems throughout the plant. Each flower has 5 regular parts but is in a head (cluster of flowers) numbering upwards of 10, so it is categorized with flowers that have parts “indistinguishable.”

3 thoughts on “Eupatorium rugosum

  1. Overall your pictures are very pretty. I like how you have pictures of each detail of the plant. The axil-cluster (head near top) has many flowers and the leaves are ovate (big base-narrow tip) and have serrate (toothed) margins. The stem and leaves also contain the toxin Trematol, when eat by cows (or other mammals) can poison the milk they produce and causing milk sickness in humans. It is rare today to receive milk silkness but killed many individuals in the past.

  2. Great close up of the leaf! The leaf appears to be ovate in shape. I also like how you can see the stipules coming off the base.

  3. The flowers are pretty! The leaves appear to have serrated margins and arcuate venation with acute-acuminate apices. Ageratina is known for having longer petioles, too.

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