Parkinsonia aculeata
Common: Mexican palo verde, Jerusalem-thorn, Green palo verde, Horse bean
Family: Leguminoseae
Habitat: Desert valleys, elevations to 4500 ft.
Light: Full sun
Temperature: Thrives in heat. Damage occurs at 18 degrees F in young plants.
Bold color. Focal point or emphasis plant. Specimen or group adds desert effect to landscapes. Provides filtered shade for desert species. Height to 40 feet, trunk to 1 ft in diameter. Easily recognizable by its branches of long streamers, spines on branches grouped in three. High crown makes this feature tree an attractive patio, lawn or street plant.
Yellowish green bark, smooth, scaly at base and brown when larger. Leaves are bright green, twice pinnately compound, to 20 inches long. Up to 30 pairs of leaflets, each 3/16" long. Leaves fall off during drought or cold conditions. Sparse foliage provides filtered shade.
This tree blooms in late spring and early summer. Golden yellow blooms with five petals, the largest orange or yellow with orange spots. Flowers to 1" wide, in cluster to 7" long, followed by dark brown pod narrowing between seeds, to four inches long.
Gradually becoming naturalized in Arizona. Foliage and seeds are eaten by wildlife. A favorite of bees. Only one species of Parkinsonia in Arizona. Somewhat susceptible to mistletoe infestations. Can be seriously injured by palo verde borers which feed on roots under the soil surface. Symptoms include loss of vigor and dead branches.