Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Olneya tesota, Desert Ironwood

Desert Ironwood has beautiful and showy flowers. This species is relatively rare in the United States where it is found only in Arizona and California. Olneya tesota Desert Ironwood is a native tree or large shrub that blooms from May to June. Desert Ironwood is common along dry washes in desert foothills below 2,500 feet. Olneya tesota Desert Ironwood has pretty flowers, showy pale lavender or purple with white areas. Olneya tesota Desert Ironwood has green or grayish-green leaves, mostly evergreen, and sharp spines making landscape plants difficult to work on or around. Olneya tesota Desert Ironwood is a member of the Fabaceae or Legume Family. Fruits are dehiscent legumes with 1 or more seeds. Olneya tesota Desert Ironwood is “Salvaged Assessed, Harvest Restricted” in Arizona; A permit from the Department of Agriculture in necessary to transport this plant off private property. Olneya tesota

Scientific Name: Olneya tesota
Common Name: Desert Ironwood

Also Called: Desert-Ironwood, Ironwood (ES: Palo Fierro, Palo de Hierro, Tèsota)

Family: Fabaceae or Leguminosae Family

Synonyms: ()

Status: Native

Duration: Perennial

Size: Up to 30 feet (9.1 m) or more (35 feet - 10.7 m).

Growth Form: Desert Ironwood is a very slow growing desert tree or shrub with numerous sharp spines.

Leaves: Desert Ironwood has green or grayish-green leaves that are generally evergreen; the leaves are pinnately compound with 8 or more oval leaflets.

Flower Color: Desert Ironwood has showy, pale lavender or purple flowers with white; the flowers are pea-like and the fruit is a thick pod with 1 or more seeds.

Flowering Season: April or May and June.

Elevation: Usually below 2,500 feet (762 m) or so; below 4,200 feet (1,300 m) in California.

Habitat Preferences: Desert Ironwood is common in rocky and sandy soils and along dry washes in desert foothills.

Recorded Range: The Desert Ironwood is a relatively rare plant in the United States where it is native to Arizona and California. In Arizona it is found in the central and wester parts of the state and in California it is native to the southeast corner. It is also found throughout Baja California and central and northern Mexico.

North America & US County Distribution Map for Olneya tesota.

North America species range map for Desert Ironwood, Olneya tesota:

North America species range map for Desert Ironwood, Olneya tesota:
Click image for full size map.

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown
Wetland Indicator: Unknown

Threatened/Endangered Information: In Arizona, pursuant to Title 3, Chapter 3, A.R.S. § 3903(B)(3), Olneya tesota is "Salvage Assessed, Harvest Restricted" (A permit from the Department of Agriculture is necessary to transport this species off private property).

Genus Information: In North America, USDA Plants Database lists 1 monotypic species for Olneya. Worldwide, World Flora Online includes 1 accepted species names. The genus Olneya was published in 1854 by Asa Gray, (1810-1888).

In the Southwestern United States: Arizona and California both have 1 species of Olneya, Nevada, New Mexico, Texas and Utah have 0 species. Data approximate, subject to revision.

Comments: This desert tree is a major species in the western Sonoran Desert community with other species such as Palo Verde, Saguaro, Ocotillo, Brittlebush, Creosote Bush, and Mesquite. Desert Ironwood is generally thought to be an indicator species of the Sonoran Desert in North America, Baja California and Mexico.

Ironwood Forest National Monument in south-central Arizona is named for Olneya tesota.

Desert Ironwood has a low tolerance for frost, its presence was also used as an "indicator" species in selecting sites for citrus orchards.

The type specimen for Olneya tesota was collected along the Gila River in Arizona, exact location unspecified.

Importance to Wildlife, Birds and Livestock
Desert Ironwood, Olneya tesota has attractive flowers, the flowers, their seeds and plants may be visited by hummingbirds and/or small mammals including rodents and large seed eating birds in search of food, nectar and protection through cover.

According to Bat Biologist Dr. Ginny Dalton, the Lesser Long-nosed Bat (Leptonycteris curasoae yerbabuena) is thought to migrate northward following the bloom of the Desert Ironwood tree. These bats have been documented to follow the bloom of other plant species as well. This bat ranges from the southern tip of Baja California north into Arizona and California and perhaps other southwestern states. The winter range is southward into Central America.

Beneficial Value to Butterflies, Honey Bees and Insects
Desert Ironwood, Olneya tesota has attractive flowers, the flowers and their plants may be visited or used by butterflies, moths, flies, honeybees, native bees and other insects in search of nectar, food or shelter and protection.

Etymology:
The genus “Olneya” (Ol'neya:) was named after Stephen Thayer Olney (1812-1878), a Rhode Island botanist and woolen manufacturer.

The genus Olneya was published in 1854 by Asa Gray, (1810-1888).

The genus Olneya is a monotypic genus.

The species epithet tesota (teso'ta:) is a corruption of the Spanish tieso meaning "stiff or firm". Tesota is a southwest Native American name for this tree.

Ethnobotany
Ethno-Herbalist: Southern California Ethnobotany; Ethnobotany of Southern California Native Plants:Olneya tesota.

Ethnobotany - Native American Ethnobotany; University of Michigan - Dearborn
Desert Ironwood, Olneya tesota is used by southwestern United States indigenous peoples for such purposes described below.
  • Cahuilla Food, Staple; Roasted pods and seeds ground into flour.
  • Cahuilla Other, Fuel; Wood used for firewood.
  • Cahuilla Other, Tools; Wood used to make implements requiring extreme hardness: throwing sticks and clubs.
  • Cocopa Food, Porridge; Seeds roasted, ground and made into mush.
  • Mohave Food, Bread & Cake; Seeds parched, ground lightly, roasted and the meal made into thin loaves and baked.
  • Mohave Food, Dried Food; Seeds parched, ground lightly, roasted and eaten.
  • Papago Fiber, Building Material; Posts of wood, forked at the top, used for the core of the house frame.
  • Papago Food, Dried Food; Beans flailed, winnowed, parched and used for food.
  • Papago Food, Dried Food; Seeds basket winnowed, parched, sun dried, cooked, stored and used for food.
  • Papago Food, Staple; Beans parched, sun dried, stored, ground into flour and used as a staple food.
  • Papago Food, Unspecified; Ground, leached seeds used for food.
  • Papago Other, Musical Instrument; Concave sticks with far-spaced, deep notches used as loud rattles for scraping stick songs.
  • Papago Other, Tools; Four foot sticks with sharp points used as digging sticks.
  • Papago Other, Tools; Wooden stakes driven into the ground and used for weaving cotton.
  • Pima Food, Dried Food; Beans formerly pit roasted, parched and eaten whole.
  • Pima Food, Dried Food; Nuts parched and eaten.
  • Pima Food, Dried Food; Seeds formerly dried, roasted, ground coarsely and used for food.
  • Pima Food, Dried Food; Beans formerly pit roasted, parched and eaten whole.
  • Pima Other, Fuel; Wood used for firewood.
  • Pima Other, Tools; Formerly used to make shovels.
  • Pima Other, Tools; Wood used to make tool handles.
  • Pima, Gila River Food, Unspecified; Seeds leached, roasted and eaten.
  • Pima, Gila River Food, Unspecified; Seeds parched and eaten.
  • Seri Food, Porridge; Beans ground into a meal, mixed with water or sea lion oil and eaten.
  • Yavapai Food, Bread & Cake; Dried, mashed, parched seeds ground into a meal and used to make greasy cakes.
  • Yavapai Food, Staple; Dried, mashed, parched seeds ground into a meal and used to make greasy cakes.
  • Yuma Food, Bread & Cake; Seeds parched, ground lightly, roasted and the meal made into thin loaves and baked.
  • Yuma Food, Dried Food; Seeds parched, ground lightly, roasted and eaten.

  • See complete listing of ethno-botanical uses at Native American Ethnobotany, University of Michigan, Dearborn.

    Date Profile Completed: 09/03/2015, updated 02/21/2022
    References and additional information:
    Arizona Flora, Kearney Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, California.
    Plants.USDA.gov; Department of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed on-line; 02/21/2022.
    https://plants.usda.gov/home/plantProfile?symbol=OLTE
    https://plants.usda.gov/home/basicSearchResults?resultId=a63b7895-5f7d-45d7-8853-6c0491756b40
    World Flora Online; A Project of the World Flora Online Consortium; An Online Flora of All Known Plants - (accessed on-line; 02/21/2022)
    http://www.worldfloraonline.org/search?query=olneya
    Native Plant Information Network, NPIN. Published on the Internet http://www.wildflower.org/plants/; accessed on-line 02/21/2022. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
    https://www.wildflower.org/plants/result.php?id_plant=OLTE
    Wiggins 1964, Felger 200; Editors: S.Buckley, 2011; from SEINet Field Guide, on-line; accessed 02/21/2022.
    https://swbiodiversity.org/seinet/taxa/index.php?taxon=1410
    Matt Lavin &: Duane Isely 2012, Olneya tesota, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=35105, accessed on February 21, 2022.
    The University of Arizona, Campus Arboretum - Dunbar Spring Neighborhood - Olneya tesota, on-line; accessed 02/21/2022.
    https://arboretum.arizona.edu/dunbar-spring-neighborhood-olneya-tesota
    Wikipedia contributors. "Olneya." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 19 Dec. 2021. Web. 21 Feb. 2022.
    Dr. Ginny Dalton, Bat Biologist, Lesser Long-nosed Bats: Why Do They Migrate? "Signs of Spring, Journey North" - (accessed on-line; 02/23/2022).
    http://www.learner.org/jnorth/tm/spring/Bats_LeptoRangeMap.html
    Seiler, John, Peterson, John, North American species range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
    http://dendro.cnre.vt.edu/dendrology/
    SEINet synonyms, scientific names, geographic locations, general information.
    http://swbiodiversity.org/seinet/
    Etymology: Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed on-line; 02/21/2022)
    http://www.calflora.net/botanicalnames/pageO.html
    http://www.calflora.net/botanicalnames/pageT.html
    IPNI (2020). International Plant Names Index. Published on the Internet http://www.ipni.org, The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. [Retrieved on-line; 21 February 2022].
    https://www.ipni.org/?q=olneya