Scientific:
Ebenopsis ebano (Synonyms: Chloroleucon ebano, Mimosa ebano, Pithecellobium ebano, and Pithecellobium flexicaule)
Common: Texas ebony, ebony blackhead, ape's earring
Family: Fabaceae (Leguminosae)
Origin: Far south Texas south into old Mexico
Pronounciation: E-ben-OP-sis e-BAN-oo
Hardiness zones
Sunset 12-13
USDA 8 (some dieback due to cold) to 11 (best in arid and semi arid regions)
Landscape Use: Slow growing but eventually becoming a large upright shade tree for oasis and xeric landscapes, surprisingly a great bonsai tree.
Form & Character: Stiff, don't get too close, stately, green + desert = prime tree for Phoenix urban areas.
Growth Habit: Evergreen, woody, broadleaf perennial tree, slow growth rate to eventually 40-feet height and spread with multiple trunks; bark smooth when young to rough and fissured with age. Young branches extend in a characteristic zig-zag pattern. Don't believe the "reports" that this is really a little tree, it just grows slow is all. Very briefly deciduous in late spring before flowering if grown in a no irrigation area, otherwise evergreen.
Foliage/Texture: Alternate, pinnately compound leaf with 3 to 5 pairs of oblong to obovate, small leaflets, medium green, hidden stipular spines to 1/2-inch long set under foliage; medium texture.
Flowers & Fruits: Small, musty fragrant, cream-colored flowers in dense, slender, terminal spikes to 1.5-inches long, flowers strongly attract bees. Fruit are an immense dark brown pods 6- to 12-inches long, sometimes curved or contorted, segmented, tardily dehiscent.
Seasonal Color: Cream yellow-colored flowers in early summer, but can also flower after monsoon in early fall. Fruit pods are persistent and visible. From an ornamental perspective, the fruit are big, bad, and ugly, and are the only non-aesthetic part of this tree.
Temperature: Tolerant of Phoenix heat and cold, however, sunscald on exposed southwestern sides of tree trunks is common. Texas ebony will drop its leaves and go deciduous if air temperatures fall into the low 20oFs, and will have stem dieback if temperatures fall below 20oF.
Light: Full sun
Soil: Highly tolerant of desert soils.
Watering: Texas ebony is very drought tolerant once established. Providing supplemental water to young specimens will increase growth rate.
Pruning: Like other arid-zone trees, Texas ebony in its native habitat will grow a dense canopy to the ground. Given this habit, the selection of scaffold branches when training young specimens and crown raising over time are the principal pruning techniques that real horticulturists will practice to train specimens into typically what are beautiful single or multi-trunk landscape trees with upright and broadly spreading canopies at maturity.
Pruning Abuse: Sadly, the 'Horticultural clods of Phoenix' (aka 'Hort clods' - untrained persons armed with gas-powered hedge trimmers and leaf blowers) seem to always want to shear these trees when young into a large cartoon-like "lollypop-on-a-stick" or an "odd-looking table top" just like all the other 'sheared shrubs' in Phoenix. Young Texas ebony trees brutalized in this manner will grow a dense matrix of crossing and intermingled branches. Eventually these young, victimized trees will grow too large to continue this (in)effective malpractice (I call them "trees with a sidewall haircut"). Trees abused and mis-shapened like this will likely need years and years worth of corrective or restorative pruning or else should be removed and replaced. Please don't be a 'Hort clod'.
Propagation: The seeds have an unusually hard epiderm (coat) that needs a scarification treatment (soaking in 95% sulfuric acid, processing in a rock tumbler, or manually chipping or filing) in order to readily germinate.
Disease and Pests: Palo verde borer beetle larvae can occassionally be a problem with Texas ebony in Phoenix during summers.
Additional comments: Texas ebony is a slow-growing and beautifully spreading tree that needs an appropriately large landscape space to slowly and gracefully mature. Sadly though, Texas ebony is often mis-cast in the landscape as a small feature. Beware of the stipular spines at the base of the leaves that can draw blood! Being well armed, Texas ebony can be vicious to work with. Trained and knowledgable folks (ISA Certified Arborists) will wear proper attire and protective equipment, ie., gloves, long sleeve shirts and pants, and protective eye wear when working with these beautiful trees.
For you woodworker types: In wood working circles, this tree is known for its rich heartwood that is described as dark reddish-brown tinged with purple. The heartwood is unusally close grained, strong, dense and oily. Woodworkers report that it finishes naturally with a robust luster. Ebenopsis is a small genus consisting of two species native to the United States.