Blooming with state pride

The popular palo verde, with its strong form, smooth green bark and spectacular bright yellow flowers in the spring, was officially adopted as the Arizona state tree in 1954.

  The legislation did not specify a particular variety, stating only that the palo verde (genera Cercidium) shall be the state tree.

  Two species native to Arizona are Parkinsonia floridum, commonly referred to as blue palo verde, and Parkinsonia microphylla, which is also found by the names foothill palo verde and little leaf palo verde.

   Blooming in the spring, they are beautiful trees that add vibrant color to the desert. A hybrid palo verde was introduced to the nursery trade in 1987 by the Arizona Sonora Desert Museum aptly naming the tree Desert Museum palo verde (Parkinsonia x).

  Beginning in March, palo verde trees provide us with a show of color. In Mexico, this experience is called “lluvia de oro,” meaning "shower of gold."

  The blue palo verde blooms first, producing masses of flowers. In two or three weeks, the foothill palo verde follows it. Desert Museum palo verde has the longest bloom period, flowering from March through early summer.

  The name palo verde literally translates to “green stick” or “green pole,” describing the unusual green branches and trunks of these desert trees.

  Palo verdes are easily distinguishable by their flowers. The upper petal of the blue palo verde is a solid yellow just like the other four petals. The flowers cover the tree in spring, and sometimes bloom again in late summer.

Blue palo verde

  Blue palo verde is a drought-resistant deciduous tree, reaching heights up to 30 feet tall with a short trunk and smooth bluish-green bark. It is a moderate- to fast-growing (with regular watering) desert tree that grows naturally in areas with good soil in the Sonoran Desert.

  These trees will normally be found in washes and other areas close to water. Very low water is required once it is well established, but regular water will increase its shading and energy-saving effectiveness.

Foothill palo verde

  Foothill palo verde is a multitrunked, deciduous large shrub or tree eventually reaching a size of 20 feet tall and wide, with yellow-green bark. It is recommended to plant as large a specimen as your budget will allow due to its slow growth rate.

  This tree is more drought-resistant than the blue palo verde and is not restricted to washes, making it more suitable to rocky landscapes.

  The foothill palo verde produces pale yellow blooms with the upper petal a solid white while the rest of the petals are yellow. Keep in mind both it and the blue palo verde have thorns and produce seed pods in the summer.

Desert Museum palo verde

  The Desert Museum palo verde is a small to medium, thornless hybrid tree with a symmetrical, rounded crown and smooth, lime-green bark. This tree has the best features combined of the blue palo verde, foothill palo verde and Mexican palo verde.

  The leaves have a more willowy feel, the growth rate is fast and the flowers are a bright golden yellow with a longer blooming period and larger than the other species.

  Desert Museum makes an excellent accent tree in any desert landscape or patio garden growing up to 25 feet high and wide. The canopy makes a good nesting site for a variety of birds, as well as shelter and cover.

  Plant the Desert Museum palo verde from a five- or 15-gallon container into well-drained desert soil, in full sun, giving it plenty of space. Dig a hole several times wider than the root ball, and about the same depth.

  Water immediately after planting. Take care not to overwater this tree to speed up growth. Too much water will lead to a weakened branch structure, making the tree more susceptible to broken or split branches in high winds.

  Palo verde trees are best suited to desert landscapes where watering is limited, rather than near lawns or flowerbeds.

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Debi Papp is a member of the Yuma Garden Club and various other gardening organizations. She can be reached at 783-3189 or greenthumbs1@roadrunner.com.