Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Ageratina herbacea, Fragrant Snakeroot

Fragrant Snakeroot flowers are white, small and attractive. Fragrant Snakeroot flowers consist of disk flowers only. This species blooms from June to October. Ageratina herbacea Fragrant Snakeroot flowers have no “ray” flowers and the “disk” flowers are pretty with exserted stamens with thin white wavy filaments as shown in the photo. Ageratina herbacea Fragrant Snakeroot grows in elevations between 5,000 and 9,000 feet and prefers multiple habitat types; openings in pine forest communities, rocky slopes, meadows, ridges, washes and along streams. Ageratina herbacea Fragrant Snakeroot leaves are yellow-green or grayish, opposite and noticeably veined. Leaves may be smooth or hairy, heart-shaped and with small soft hairs. The margins are variable. Ageratina herbacea

Scientific Name: Ageratina herbacea
Common Name: Fragrant Snakeroot

Also called: Apache Snakeroot, Herbaceous Joepieweed

Family: Asteraceae, Sunflower Family

Synonyms: (Ageratina betulaefolia, Eupatorium arizonicum, Eupatorium herbaceum, Eupatorium occidentale var. arizonicum, Kyrstenia betulifolia)

Status: Native

Duration: Perennial or subshrub

Size: Up to 2 feet (60 cm) tall.

Growth Form: Forb/herb; subshrub, woody crowns and woody rhizomes; stems green erect; stems fuzzy, covered with small soft erect hairs (puberulent), often brittle.

Leaves: Yellow-green or grayish, opposite; leaves with small stalks (petiole); leaf shape triangular or heart-shaped to broadly ovateovate; leaf margins toothed.

Flower Color: White, showy; fuzzy flowers in dense open clusters on short stalks (peduncles about 10 to 20 disk (discoid) flowers, no ray florets; corollas white, tubular with protruding (exserted) stamens and thin white wavy filaments; the fruit is a cypsela with a rough or bristly tan or brownish pappus.

Flowering Season: May, June or July to October or November

Elevation: 5,000 to 9,000 feet

Habitat Preferences: Multiple habitat types, openings in pine forest communities, pine-oak, pinyon-juniper, rocky slopes, meadows, ridges, washes and rocks along streams.

Recorded Range: A southwestern species in the United States where it may be found in AZ, CA, CO, NM, NV, TX and UT. Also found in northern Mexico. Ageratina herbacea is most heavily represented in AZ and NM. In Arizona throughout much of state, absent in the southwest corner; south to Mexico, Chihuahua, Coahuila, Sonora and Baja California.

North America & US County Distribution Map for Ageratina herbacea.

North America species range map for Ageratina herbacea:
North American range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation

North America species range map for Ageratina herbacea: Click image for full size map
Click image for full size map

U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available.

Genus Information: 15 species in Ageratina in the United States. Ageratina is mostly a southern and western genus with two solid eastern species. World wide, The Plant List includes 334 accepted species names and includes a further 127 of infraspecific rank for the genus Ageratina.
The genus Ageratina was published in 1841 by Edouard Spach.

In the Southwestern United States: Arizona has 5 species of Ageratina, California has 4 species, Nevada and Utah each have 2 species, New Mexico has 3 species and Texas has 5 species. All data is approximate and subject to taxonomic changes.

Comments: Fragrant Snakeroot is found in Arizona in forested areas and is fragrant as the name implies. It is not a desert species but might be encountered. It superficially resembles Brickellbush plants of the genus Brickellia; although both are in the same tribe they have technical differences in their flowers and leaves. The plants above were photographed in late July near Mount Ord in Maricopa County as they were just starting to bloom.
Fragrant Snakeroot has distinctive colored leaves which are usually yellow-green, sometimes grayish.

Importance to Wildlife, Birds and Livestock
Ageratina herbacea seeds may likely be eaten by birds and small mammals.

Special Value to Native Bees, Butterflies and Insects
Ageratina herbacea flowers may be visited by butterflies, bees and other small insects.

The genus Ageratina (Agerati'na:) is diminutive of Ageratum from Greek "ageratos" or "ageraton" which means "not growing old", a reference to the flowers which retain their color for a long time.
The genus Ageratina was published in 1841 by Edouard Spach.

The specific epithet, herbacea (herba'cea:) means herbaceous and not woody.

Ageratina herbacea has been used for headaches and fevers by Southwestern indigenous peoples;
  • Navajo, Ramah Drug, Analgesic; Cold infusion taken and used as lotion for headache.
  • Navajo, Ramah Drug, Febrifuge; Cold infusion taken and used as lotion for fever.

  • See full species account from Native American Ethnobotany, University of Michigan, Dearborn.

    Date Profile Completed: 8/26/2012; updated 04/19/2020
    Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, as Eupatorium herbaceum.
    U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 04/19/2020) for Ageratina.
    The Plant List (2013). Version 1.1. Published on the Internet; (accessed 04/19/2020).
    David J. Keil 2012, Ageratina herbacea, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=749, accessed on April 19, 2020.
    Guy L. Nesom, FNA | Family List | FNA Vol. 21 | Asteraceae| Ageratina; 7. Ageratina herbacea (A. Gray) R. M. King & H. Robinson, Phytologia. 19: 222. 1970.; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
    FNA 2006, Kearney and Peebles 1969, McDougall 1973; Editors; L.Crumbacher 2011, F.S.Coburn 2015, A.Hazelton 2015 from SEINet Field Guide, on-line; - (accessed 04/19/2020).
    'Ageratina herbacea', Wikipedia, The Free Encyclopedia, 9 November 2018, 12:24 UTC, [accessed 20 April 2020
    SEINet synonyms, scientific names, geographic locations, general information
    Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 04/19tan /2020)