Arid Zone Trees

Pithecellobium

A respected desert landscape designer once quipped that Texas Ebony trees were too green to be a desert tree. Due in part to a slow growth rate and chronic lack of saleable trees, Texas Ebony (Pithecellobium flexicaule) is among the most under-utilized and under appreciated arid landscape tree. The common name itself is a misnomer since the wood is dark mahogany to purple or brown, not black. The trees are highly drought tolerant, slow growing and are moderately cold hardy to 25 F and may be damaged or killed below 20 F. Leaves are made-up of clusters of shiny, dark green leaflets. Branches are highly spined and zig-zag at each node. Branching is usually dense resulting in a thick canopy that casts dense shade. This combination of thorns and dense branching makes Texas Ebony ideal for security screen plantings. It is also used as an accent tree with its striking dark green leaf color, smokey grey bark and semi deciduous growth habit. The tree prefers well drained soils and full sun. Young trees require pruning to insure that they will mature with desirable shape. Clusters of fragrant yellow or white flowers are produced from May to October with 4 to 6 inch seed pods maturing within 30 days. Pods split open naturally to release most seeds. Reports suggest that Texas Ebony can grow to 15 to 30 feet.

ANOTHER excellent Pithecellobium specie, that has only recently come into commercial production is P. mexicanum. Some common names for this specie include Mexican Ebony or Palo Chino. This tree is found growing in the Mexican states of Sonora, Sinaloa and southern Baja. Mexican Ebony has a handsome open canopy and branching pattern and has a growth rate comparable to Chilean Mesquite. Both the foliage and immature bark are a pale gray-green, similar to Ironwoods. This deciduous tree is hardy to 18 F and armed with cat-claw like thorns. In natural settings trees are found growing in arroyos, desert slopes and valley floors. They cannot be naturalized and require some summer irrigation. Cream colored blooms appear in March and April with 1 to 3 inch long, thick brown pods maturing by mid-summer.

STILL ANOTHER Pithecellobium specie that could be used in southwestern landscape is P. pallens. The two reported common names are Tenaza or Ape's Earring. Some literature suggests that the tree actually grows as a large shrub, maturing at 10 to 15 feet. Its growth rate and mature size have not been fully evaluated under southwestern growing conditions. Branches are long and straight with small thorns on old and new growth. Leaves resemble those of Sweet acacia with multiple small, light green leaflets. From May to August (generally after rains) clusters of creamy white, fragrant ball flowers cover the branches. These flower displays are very showy and add to the value of Tenaza as an accent or specimen tree. It has a fairly fast growth habit and takes full sun. It is not as drought tolerant as the other two Pithecellobium species discussed.

With their unusual color, faster growth habits and unique structure, P. mexicanum and P. pallens. will be excellent additions to the desert landscape pallet. Field evaluation of both species, under nursery conditions, is on-going.

Arid Zone Trees Dedicated to providing quality trees to the Landscape Industry that are appropriate to the Desert Southwest
© Copyright 2005 Arid Zone Trees		Pithecellobium A respected desert landscape designer once quipped that Texas Ebony trees were too green to be a desert tree. Due in part to a slow growth rate and chronic lack of saleable trees, Texas Ebony (Pithecellobium flexicaule) is among the most under-utilized and under appreciated arid landscape tree. The common name itself is a misnomer since the wood is dark mahogany to purple or brown, not black. The trees are highly drought tolerant, slow growing and are moderately cold hardy to 25 F and may be damaged or killed below 20 F. Leaves are made-up of clusters of shiny, dark green leaflets. Branches are highly spined and zig-zag at each node. Branching is usually dense resulting in a thick canopy that casts dense shade. This combination of thorns and dense branching makes Texas Ebony ideal for security screen plantings. It is also used as an accent tree with its striking dark green leaf color, smokey grey bark and semi deciduous growth habit. The tree prefers well drained soils and full sun. Young trees require pruning to insure that they will mature with desirable shape. Clusters of fragrant yellow or white flowers are produced from May to October with 4 to 6 inch seed pods maturing within 30 days. Pods split open naturally to release most seeds. Reports suggest that Texas Ebony can grow to 15 to 30 feet. ANOTHER excellent Pithecellobium specie, that has only recently come into commercial production is P. mexicanum. Some common names for this specie include Mexican Ebony or Palo Chino. This tree is found growing in the Mexican states of Sonora, Sinaloa and southern Baja. Mexican Ebony has a handsome open canopy and branching pattern and has a growth rate comparable to Chilean Mesquite. Both the foliage and immature bark are a pale gray-green, similar to Ironwoods. This deciduous tree is hardy to 18 F and armed with cat-claw like thorns. In natural settings trees are found growing in arroyos, desert slopes and valley floors. They cannot be naturalized and require some summer irrigation. Cream colored blooms appear in March and April with 1 to 3 inch long, thick brown pods maturing by mid-summer. STILL ANOTHER Pithecellobium specie that could be used in southwestern landscape is P. pallens. The two reported common names are Tenaza or Ape's Earring. Some literature suggests that the tree actually grows as a large shrub, maturing at 10 to 15 feet. Its growth rate and mature size have not been fully evaluated under southwestern growing conditions. Branches are long and straight with small thorns on old and new growth. Leaves resemble those of Sweet acacia with multiple small, light green leaflets. From May to August (generally after rains) clusters of creamy white, fragrant ball flowers cover the branches. These flower displays are very showy and add to the value of Tenaza as an accent or specimen tree. It has a fairly fast growth habit and takes full sun. It is not as drought tolerant as the other two Pithecellobium species discussed. With their unusual color, faster growth habits and unique structure, P. mexicanum and P. pallens. will be excellent additions to the desert landscape pallet. Field evaluation of both species, under nursery conditions, is on-going.