Native Australian Acacia species have been being introduced to desert southwest landscapes for over 20 years. In many instances these species offer slightly different appearances, colors and textures than is typically found in indigenous desert trees.

Acacia pendula (Weeping Acacia or Weeping Myall) combines a strongly weeping leaf and branch canopy with blue-gray foliage to create a striking and unusual accent tree. Individual leaves are narrow, lance-shaped and range from 1 1/2" to 4" long. The leaves, like the branches are pendulous and droop toward the ground producing a rounded, relatively dense canopy. Mature trees range in height from 20 to 30 feet but not as wide.

As trees mature, some pruning and shaping of lower branches can help accentuate the cascade effect of the upper branches. As trees mature growth slows and little, if any, pruning is necessary. It grows best in full sun and well draining soils. In spite of its lush appearance, it is not well adapted for planting in turf areas. Weeping Acacia produces small pale yellow ball flowers from April to May. Flowers mature by mid summer to narrow, winged seed pods.

Trees are arid adapted but will not naturalize to survive on typical annual desert rainfall. Deep monthly irrigations of mature trees helps promote a deep and well distributed root system. Weeping Acacia makes a striking and even dramatic accent or focal point tree. The nature of the canopy and the dense shade produced limits the growth of flowering under-story shrubs. This evergreen and thornless Acacia can easily be combined with more traditional landscape trees and mixed well with other arid adapted species.

Increasingly landscape designers are seeing a need for trees that will fit into courtyard areas or small residential lots. Acacia notabilis, Notable Wattle, is a small stature evergreen Australian native that is well suited for such applications. Mature trees grow to 9 to 12 feet with a leaf canopy about as wide. Leaves are blue-green in color, oval lance-shaped, 2 to 6" long and 1/4 to 1" wide. The tree has a dense, bushy growth habit producing a spreading canopy that give it a lush texture and appearance.

It is well adapted to arid conditions and desert soils. It can be left unpruned and will develop a rounded, mounding canopy that extends to the ground or it can be pruned into a tree form with graceful multiple trunks. High numbers of densely packed yellow ball flowers are produced all along the branches at the leaf nodes making for a striking floral display. Flowers appear from about January to May. It can be used as a low growing color/accent tree, used in masses as a low dense hedge planting, as a background planting for flowering shrubs or in any setting where space is limited.

Cold hardiness for both species discussed have not been fully evaluated. Both have survived 15 degrees F without damaged in field tests in the Tucson area.