Green trunks in the desert

Reports from the desert lands of the Southwest that the palo verde trees are in gorgeous bloom there, in gaudy yellow display:

(#1) Note green branches; the trunks are green too

Just stunning. Unfortunately, the pollen is intensely allergenic, so the trees are mixed blessings.

From Wikipedia:

Parkinsonia florida, the blue palo verde (syn. Cercidium floridum), is a species of palo verde [in the legume / pea / bean family] native to the Sonoran Deserts in the Southwestern United States and Northwestern Mexico. Its name means “green pole or stick” in Spanish, referring to the green trunk and branches, that perform photosynthesis.

(#2) Blue palo verde tree

Parkinsonia florida grows to heights of 10–12 metres (33–39 ft). It is a rapidly growing large shrub or small tree, and rarely survives to 100 years. Compared to the closely related Parkinsonia microphylla (foothill paloverde), it appears more decumbent in overall form, is taller, and matures more quickly.

The plant’s trunk, branches, and leaves are blue-green in color, hence the common name. The plant is drought-deciduous, shedding its foliage for most of the year, leafing out after rainfall. Photosynthesis is performed by the blue-green branches and twigs, regardless of absent leaves.

The flowers are bright yellow, and pea-like, which cover the tree in late spring. They attract pollinators such as bees, beetles, and flies. They are followed by seed pods which are slightly larger and flatter and have harder shells than the foothill paloverde. These are a food source for small rodents and birds.

With apologies to Edward Lear on the Jumblies:

Far and few, far and few,
Are the lands where the palo verdes thrive.
Their trunks are green
And their branches too
And they use their color to survive.

We’ve seen this color adaptation before, in two trees in the genus Ceiba. On this blog:

on 4/30, in “Prickly silk”, on

Ceiba speciosa: In younger trees, the trunk is green due to its high chlorophyll content, which makes it capable of performing photosynthesis when leaves are absent; with age it turns to gray.

on 5/1, in “Stanford Arizona III”, on Ceiba pentandra


One Response to “Green trunks in the desert”

  1. Bob Richmond Says:

    I grew up with Mexican palo verde (Parkinsonia aculeata) in San Antonio, where it’s often called retama. It’s probably native there. It’s a serious invasive in Hawai’i and other Pacific islands, and in Australia.

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