The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, February 26, 2006

Blackbrush Acacia Is in Full Bloom
by Ro Wauer

Blackbrush acacia, sometimes called "Chaparro Prieto," is currently in full bloom throughout much of South Texas. This thorny little tree or shrub possess white to light-yellow flowers that appear in cylindrical spikes; they can be so abundant that they literally dominate the branch. The leaves are alternate and compound, with two to four (rarely five) pairs of leaflets, and they possess straight spines. Most people, as well as bees, appreciate these lovely shrubs when flowering; they make especially good honey. However, like the closely related huisache trees, with their bright yellow and scented flowers, they can take over a field and be a problem to ranchers.

Four additional species of acacias, beside blackbrush and huisache, occur within the Texas Coastal Bend region. Catclaw (Acacia greggii) also possesses creamy yellow flowers that appear in cylindrical spikes, although it normally blooms from April to October. And catclaw spines are decurved, not straight like blackbrush. Fern acacia (Acacia angustissima) and guajillo (Acacia berlandieri) possess white to cream flowers that are rounded instead of cylindrical. Guajillo can flower most of the year, from February to December, while fern acacia flowers from April to October. Finally, twisted acacia or huisachillo (Acacia schaffneri) flowers are orange-yellow in color, very much like huisache, and bloom from February to April. They can be most common after spring rains. This last acacia differs from huisache by its spreading growth (not tree-shaped) and narrower and longer seed pods.

Acacias, all members of the legume or pea family, are widely distributed in warm regions around the world, where there are about 600 species; 300 occur in Australia. Ten species are native to Texas, and all of the Texas acacias flower in the spring and occasionally in the summer following rain. The genus Acacia means hard, sharp point, in reference to the prominent spines. All are semi-hardy and most are evergreen.

The legume family, or Leguminosae, is extremely large, with many representatives worldwide. Others in Texas include mesquite, mimosa, redbud, senna, retama, mountain laurel, and even clover and bluebonnets. Acacias and mimosas are often so similar they are difficult to tell apart. But the key difference is in the flowers themselves: acacia flowers possess numerous (20-100) stamens, while mimosas possess 10 to fewer stamens per flower. And mimosa fruits (pods) are flattened and somewhat contorted.
All these shrubs and trees are lovely when in flower!


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