Arizona State Tree

Blue Palo Verde

Tree, a Arizona state symbol: Palo Verde

(Parkinsonia florida)


(Cercidium updated to Parkinsonia)

Adopted in 1954.

The Palo Verde Tree (Genera Cercidium) was selected by the Legislature as the official state tree of Arizona in 1954. The Arizona House of Representatives approved House Bill No. 227 on March 23, 1954 and the Senate followed suit on April 3, 1954.

 Governor John Howard Pyle signed this legislation less than a week later on April 9, 1954. The original legislation refers to the genus Cercidium. The genus has been updated to Parkinsonia. There are two species that are native to Arizona and these are the varieties listed below. They are Parkinsonia florida, commonly referred to as the blue palo verde and Parkinsonia microphylla, commonly referred to as the yellow palo verde.

Arizona State Tree: Blue Palo Verde

Tree, a Arizona state symbol: Palo Verde

Palo Verde is from the Spanish meaning "green stick" or "green pole." It is found in the desert and desert foothill regions of Arizona.

When the Palo Verde tree blooms, either in April or May depending on the elevation, it is a blaze of shimmering yellow-gold. Two species are native to Arizona: the Blue Palo Verde and the Foothill Palo Verde which is yellow-green.

Deciduous tree, 30', flowers yellow, Mar.-May, green bark, tree bare most of the year, lower deserts of Ca., Ariz., full sun, drought tolerant, needs perfect drainage and no summer water, seeds may be ground into edible meal . Cold hardy to somewhere about 10 degrees F. We've had some killed in containers at 15 degrees F., others tolerant to below 10 degrees F. This species has the funny trait of forming water-repellent soils under it. By not allowing the water to stay under it and shedding the water out to its drip line it can out compete even the annuals. That is why you find few plants under Cercidium, mostly only the ones that are mycorrhizally linked to the Cercidium. Desert washes in Creosote woodland.

Identification of the Blue Palo Verde

Tree, a Arizona state symbol: Palo Verde
  • Form: low multistemmed tree, rounded crown
  • Seasonality: deciduous (in drought or cold)
  • Size: 15-30ft with equal spread; growth rate varies with water supply
  • Leaves: bipinnately compound, in pairs, about 1/2in long with leaflets of 1/4 to 1/8in; often leafless most of the year
  • Flowers: bright yellow pea-like blooms cover entire tree; first Cercidium to bloom in spring
  • Fruit: flat pod, single or multiple seeded; brown bleaching to white with age; 1.5-3in long
  • Stems/Trunks: normally green, growing more gray or dark and rough with age; tree has overall bluish cast; dense growth; small thorns
  • Range/Origin: Sonoran and Mohave deserts, Baja California; elevations to 4000ft
  • Hardiness: mid to low teens

Arizona House Bill 227

State of Arizona
House of Representatives
Twenty-First Legislature
Second Regular Session

H. B. 227

Introduced by Mrs. Thode of Pinal; Mrs. Anderson of Cochise; Mrs. Rosenbaum of Gila; Mesdames Burgess, Dwyer, Haberl, Kuntz, McRae of Maricopa; Mesdames Hutcheson, Willis of Pima; Mrs. Ellis of Yavapai.



Be it enacted by the Legislature of the State of Arizona:

Section 1. STATE TREE. The Palo Verde (genera cercidium) shall be the state tree of Arizona

Taxonomic Hierarchy: Blue Palo Verde

Kingdom: Plantae - Plants
    Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
    Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Rosidae
Order: Fabales
Family: Fabaceae ⁄ Leguminosae - Pea family
Genus: Parkinsonia L. - paloverde
Species: Parkinsonia florida (Benth. ex A. Gray) S. Watson - blue paloverde

State Trees
State Trees
All of the state trees, except the Hawaii state tree, are native to the state.