Come! Ms. Dunlap will give two talks at the CNPS Conservation Conference Feb. 1-3 in LA!

One regarding a database of 3,700 nectar plants (& how to collect images to benefit pollinators), and the other regarding
a prototypical key incorporating a novel plant identification system that produced an order of magnitude improvement.

Ageratina altissima

Family: Asteraceae


Synonym: Eupatorium rugosum

Native to: Eastern North America


Type: perennial

Forms: clumping, erect

Max height: 6.6 feet

Max width: 4 feet


white/off white




Attracts wildlife: adult butterfly, specific butterfly species

Bird uses plant for shelter or cover or cavity: cover

Plant features: toxic

Exposure: light shade

Propagates by: seed

flowers in summer

Soil types: gravelly or rocky, loam

USDA Zones: zone 4 -30 f, zone 5 to -20 f, zone 6 to -10 f, zone 7 to 0 f, zone 8 to +10 f, zone 9 to +20 f

Temp. range: -30 to +30 °F

Water: dry, regular

  • Ageratina altissima

Ageratina, a genus containing 337 species, is a member of the Celastraceae family. Ageratina altissima tolerates dry conditions. It grows from seed to 6½ feet tall and prefers light shade. It is a native wildflower in eastern North America.

Wikipedia discuss toxicity problems with this plant: "when the plants are consumed by cattle, the meat and milk become contaminated with toxin. When milk or meat containing the toxin is consumed, the poison is passed on to humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans."

It is possible this toxicity is part of its appeal to butterflies, as many of them nectar on plants in this genus. Blossoms of Ageratina attract the MONARCH to feed as well as numerous other butterflies.