Size: Up to 12 feet (3.7 m) or more (20 feet (6 m)).
Growth Form:Tree or large shrub; the species has paired slender white stipular spines up to 1 inch (3 cm) long as shown in the photograph above; The bark is mostly smooth, generally gray to reddish-brown in color.
Flower Color: Yellow or orange-yellow; dense globose heads; fruit a long straight pod or beans (legume), fruitpod woody or papery, compressed between seeds.
Flowering Season: April, May or later with second bloom, June, July and August.
Elevation: 2,500 to 5,000 feet (762-1,524 m).
Habitat Preferences: Dry slopes, washes, flat desert areas and mesas, arroyos and washes, sandy and sandy loam soils; often in shallow caliche- and limestone-soils; mid- to high-elevations.
Recorded Range: Whitethorn Acacia is has a disjunct geographical distribution. It is native to the southwest border states of AZ, NM and TX. It also is native to Baja California and central and northern Mexico south to Oaxaca. It is most predominant in Arizona with smaller populations in NM and TX.
Genus Information: In North America there are 34 species for Vachellia. Worldwide, The Plant List includes 32 accepted species names and a further 37 scientific names of infraspecific rank for Vachellia
The genus Vachellia was published in 1834 by Robert Wight, (1796-1872) and George Arnott Walker (1799-1868).
In the Southwestern United States: Arizona has 3 species of Vachellia, California has 1 species, Nevada has 0 species, New Mexico has 4 species, Texas has 6 species, Utah has 0 species. Data approximate, subject to revision.
Comments: Whitethorn Acacia is an attractive shrub or small tree with fragrant showy orange-yellow flowers in textured globose balls. Whitethorn Acacia is cultivated and used in desert landscaping. Because of its large sharp spines it is often used as a protective barrier hedge.
This plant is well adapted to the arid conditions of desert life and will not produce leaves or flowers in times of severe drought.
Whitethorn Acacia readily sprouts following fire and sprouting can occur as early as 1 month after fire.
Vachellia constricta, Whitethorn Acacia, provides Desert Mule Deer a small part of their diet in summer, fall and winter. Livestock will consume the fruit pods but do not appear to relish the foliage. This species is long-lived; 70 or more years.
Several small mammals, including Pack Rats, Kangaroo Rats and species of Pocket Mouse, feed on the seeds, some of these birds utilize this species more than others; rabbits most likely browse on this species in the absence of more preferable food.
Whitethorn Acacia seeds make of a significant amount of food consumed by many species of grainivorous song- and game-birds including Scaled Quail, hummingbirds, woodpeckers, flycatchers, verdins and other desert bird species.
Beneficial Value to Butterflies, Honey Bees and Insects
Vachellia constricta, Whitethorn Acacia, has attractive yellow, sweet 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. Nectar-insects, Nectar-butterflies, Nectar-bees,
U.S. Forest Service; Fire Effects Information System (FEIS)
See the U.S. Forest Service online collection of reviews of the scientific literature for management considerations of Vachellia constricta, Whitethorn Acacia are found here.
Etymology:
The genus “Vachellia” (Vachel'lia:) is named after the Rev. George Harvey Vachell (1798-1839); born in Littleport, Cambridgeshire, and graduated from Cambridge University in 1821.
The genus Vachellia was published in 1834 by Robert Wight, (1796-1872) and George Arnott Walker (1799-1868).
The species epithet “constricta” (constric'tas:) means constricted, drawn together or contracted.
