This is a variety of trees in the genus
Robinia, in the
legume family. Locusts are native to
North America, and common in the wild and in cultivation. Many have been spread by people into areas where they would not be normally found, like the foothills of the
Sierras. They have done well here, but are not as much an invasive problem as tamarisk.
These trees have compound leaves and fragrant flowers which may be white, yellow, or pink. They are extremely hardy, adapted to desert conditions as well as extreme cold. They usually naturally take on a shrubby form, maturing to tree form; up to 50 feet tall. They are good in semi-wild situations but should probably be avoided in these situations if out of their native habitat as they naturalize quickly. They divide via suckers, which will not be welcome in a manicured landscape. They also have weak wood, agressive roots, and sharp thorns. For these reasons, this tree generally isn't a street or garden tree.
Their leaves turn bright yellow in the fall, and they are covered with flowers in the spring. My most poignant memory of this tree is taking pressure bomb samples at 3 AM, hanging over a flooded creek cutting branches off amidst the thorns. This is one of those trees you can't kill if you try.