USA Official Tree of Arizona

Arizona Official State Tree (AR)

Blue Paloverde Tree, a state symbol

(Fabaceae Cercidium floridum)
Adopted in 1954.

 

The Palo Verde Tree,  Fabaceae Cercidium floridum, was selected by the Legislature as the official state tree in 1954. 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.

Description:
  • 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

 

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

 

Source:
Pima County Home Horticulture

Books about the Fabaceae Cercidium floridum (The Palo Verde Tree)