Parkinsonia aculeata

This gracefully spreading (sometimes weeping) dry-land native grows to 20-25' with feathery (compound strap-like) foliage that closes at night, 1" thorns and, in spring, yellow pea-flowers which make it a giant bouquet! S/D/GDr

There are several related trees referred to as Palo Verde, which means “green stick” in Spanish, a reference to the green trunks and branches which are characteristic of them. One of these, Parkinsonia aculeata, is commonly called Mexican Palo Verde. Though it does occur in Mexico, it is also native to the southwestern U.S. and southward as far as South America. Its natural range does not extend into California, but it is widely grown in the southern part of the state and has naturalized in some locations there. Parkinsonia aculeata is not a large tree; it may grow to be as much as 30 feet tall (9 m), but is usually less than this. Its branches have small thorns, and its fine-textured foliage yields dappled light rather than dense shade. The leaves are divided at the base into long narrow leaflets about 6 to 9 inches long (15 to 23 cm). Each of these leaflets has a flattened narrow midrib with tiny secondary leaflets arrayed on either side. This tree begins flowering in June at the Ruth Bancroft Garden and continues until cold weather arrives in the fall. The flowers are about ¾ of an inch wide (2 cm) and a vivid yellow except for the uppermost petal, called the banner, which is speckled with red or orange and becomes more deeply colored as the flower ages. Like other members of the pea family (Fabaceae), Parkinsonia aculeata has bean-like pods which encase the seeds. The pods are 2 to 4 inches long (5 to 10 cm), with constrictions between the seeds and pointed at the end.

This floriferous desert tree really puts on a show when it is in bloom. The fragrant yellow flowers with orange markings smother the tree twice a year. Bees produce an excellent honey from the flowers. The spreading, somewhat weeping crown of the tree is made up of slender twigs & very small leaves. The leaves appear during periods of moisture & drop off during drought. The tree is still able to photosynthesize (make food) without leaves because of all chlorophyll in the green colored trunk and branches. By dropping its leaves it is able to reduce the amount of water lost because of transpiration (plant sweat). Because of this it does drop a fair amount of litter, so it is best planted in the middle of a bed so you don’t have to be sweeping all the time. It has thorns too, so all the more reason to keep it away from pathways. It would make an excellent barrier through. Native to parts of South America, it is drought & heat tolerant. In fact, it prefers heat. Grows to be about 25’ tall.