The Genus Ageratina
Family: Asteraceae
There are 336 species of Ageratina in warmer regions of the Americas and West Indies. Over 150 species are native to Mexico. A few flourish in the cooler areas of the eastern United States. In our region they are often found in moist canyons.
Ageratina species belong to a group of special Asters that contain pyrrolizidine alkaloids, used by some species of butterflies to attract females, and to protect themselves, and their eggs, from predation (utilizing the toxicity of the alkaloids). Therefore this species is a butterfly magnet.
The genus, Ageratina is derived from Greek meaning 'un-aging', in reference to the flowers keeping their color for a long time.
Photo of Ageratine herbacea by Max Licher, SEINET
Desert Ageratina
Ageratina herbacea
Herbaceous shrub to about 3x3’. White, fragrant flowers appear August through October.
Regular water, part sun, hardy to at least 0°F. Cut back as needed. Plant in improved soil.
Fragrant flowers that are magnets for butterflies and other pollinators.
A cold infusion or lotion made from the foliage is used for headache, cold, or fever.
The species name, herbacea, means herbaceous.
Found in rocky areas along streams, slopes, ridges, and washes, in open pine forests and juniper woodlands, from 5,000-9,000 ft. in desert regions (Sonoran, Mojave, and Chihuahuan Deserts) of the southwestern United States (southeastern California, southern Nevada, southern Utah, Colorado, Arizona, New Mexico, western Texas) and northern Mexico (Baja California, Chihuahua, Coahuila, Sonora).
Photo by Max Licher, SEINET
Ageratina herbacea on iNaturalist
Santa Rita Snakeroot
Ageratina paupercula
Perennial herbaceous plants, often growing out of rocks, reaching up to 3’ tall, though often hanging out of cracks in rocks. White, fragrant flowers appear in spring into early summer.
Fragrant flowers that are magnets for butterflies and other pollinators.
The species name, paupercula, means poor. Probably unfairly comparing the flowers to A. herbacea, but this species still has a wonderful showing of flowers.
Plant in part sun, grow in well-drained soil with regular moisture. Cut back as needed. Hardiness unknown but probably at least into the teens °F.
Found in canyons near streams, from 3,500-5,000 ft in Arizona and Sonora, Mexico.
Ageratina paupercula on SEINET
Ageratina paupercula on iNaturalist
Wright’s Snakeroot
Ageratina wrightii
Herbaceous perennial plants reaching almost 5’ tall, though often smaller, often dangling out of rock crevices, cliffs. White, fragrant flowers appear July and continue into fall.
Plant in part sun, provide good drainage and regular water. Hardiness unknown but probably at least into the teens °F.
The species name, wrightii, is named for Charles Wright (1811-1885), a naturalist who collected specimens for Harvard.
Found on limestone substrates and alluvium on ledges and slopes, in brushy vegetation; 5,000-6,000 ft. in Arizona, New Mexico, Texas, and south through the eastern side of Mexico.
Photo by Sue Carnahan, SEINET
Ageratina wrightii on iNaturalist