Acacia rigidula

Accession Count: 2
Common Name: Blackbrush Acacia
Family Name: Fabaceae
Botanical Name: Acacia rigidula
Synonyms:
Botanical Synonyms: Vachellia rigidula
Family Synonyms: Leguminosae
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics: Acacia ridigula is a deciduous shrub with rigid, thorny branches that display rich, dark-green foliage. The one inch leaves consist of long, oval shaped leaflets that are arranged in pairs, reaching one-fourth inch in length. The light-grey bark of the blackbrush acacia really allows for the foliage of the plant to stand out. In the spring to early summer, A. ridigula blooms yellow, rod-shaped flowers that vibrantly dress most of the branch (6).
Compound: Aca rig
Geographic Origin: Texas/Northern Mexico
Ecozone Origin: Palearctic
Biome Origin:
Natural History: A. rigidula otherwise known as the “blackbrush acacia” is native to desert regions (1). Its characteristic drought tolerant features allow it to thrive in dry desert soils. It is common for this plant to be found in rocky limestone hillsides where it can scavenge for the scarce water found in its surrounding environment. A. rigidula distribution spans through North America, more specifically regions of south and east Texas, to northern regions of Mexico.
Cultivation Notes:
This species is found in the form of a large shrub or small tree (2). A. rigidula is not commonly propagated through grafting or cuttings; instead it is fairly easily propagated through seeds (3). Optimal conditions for growth include exposure to full sun and loose, well-drained sandy to loamy soils. The blackbrush acacia exhibits some degree of drought tolerance and prospers in minimal watering regiments, requiring water only once a month (6).

Ethnobotany:
Blackbursh acacia, like other species of this genus, is not used for direct human consumption although it does have some indirect forms of consumption. For example, Native Americans have used the blackbrush acacia as an ingredient in medications (4). Tea can be made from the flowers, which exhibits sedative properties. The roots of the plant also serve as a source for tea, which can be used to treat sore throats, coughing, and mouth inflammations (2). Other uses for A. rigidula include the use of its seeds to alleviate stomachaches and treat diarrhea. The leaves can also be ground into a powder to stop bleeding, relieve chafed skin and can even be used as an antimicrobial wash (4). Phytochemical stimulants found in the plant, including some amphetamines, are found in dietary supplements and weight loss medications (5). This plant also forms a small part of the diet of some wild animals. It is not the preferred source of food for deer and other animals, but it can be consumed when other food resources are scarce (1). Its flowers also provide nectar for bees and butterflies (3). 
For landscape purposes, A. rigidula works well as a physical barrier or screen but is also outstanding when displayed by itself. This plant is best suited for transition and arid zones when using xeriscape techniques. The dark, green foliage of A. rigidula makes for a great backdrop for light-colored plants, and with proper training, this shrub is able to take the form of a small tree (6).


Height: 11 - 15 feet
Width: 11 - 15 feet
Growth Rate: Slow Growing
Grow Season: ForeSummer
Flower Season: Spring
Color: Yellow
Function: Screen
Spread: Non-spreading
Allergen: Non-allergenic
Invasive: Benign
Toxicity: Benign
Hardy: Hardy
Water Use: Low water Use

Citations:

1. http://www.mswn.com/media/info_sheets/acacia_rigidula.pdf. Retrieved April 23, 2015. 


2. http://aggie-horticulture.tamu.edu/ornamentals/nativeshrubs/acaciarigid.htm. Retrieved April 23, 2015. 


3. http://www.wildflower.org/plants/result.php?id_plant=ACRI. Retrieved April 23, 2015. 


4. http://wc.pima.edu/~bfiero/tucsonecology/plants/trees_wta.htm. Retrieved April 22, 2015.


5. http://www.webmd.com/vitamins-and-supplements/news/20150407/bmpea-acacia-rigidula-supplments. Retrieved April 23, 2015. 


6. Mielke, Judy. Native Plants for Southwestern Landscapes. University of Texas Press, 1993.

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Acacia rigidula