Arizona State Tree
Foothill Palo Verde and Blue Palo Verde
In 1954, the State of Arizona named the Palo Verde as its State Tree. The legislature did not distinguish between the two species of this tree that are native to the State; therefore both the Foothill and the Blue share the honor. Perhaps the legislature was aware that there is hybridization between these two species.
Both the Blue and Foothill Palo Verdes have a number of characteristics in common, starting with the reason they are called Palo Verdes (Spanish for green stick). The name indicates that these trees can use the chlorophyll in their bark to photosynthesize and produce sugar. In general, three quarters of their food is metabolized through the bark, whereas only a quarter is produced by the leaves.
In terms of growth form, they both start with short crooked trunks or thinner multi-trunks that branch close to the ground. The Foothill’s branches tend to be stiff and upright and its crown is open and irregular, maturing usually at less than 30’, which it might attain in deep soil. The Blue tends to have large drooping branches, and maturing to 40 feet tall with a round crown.
Foothill Palo Verde
Blue Palo Verde