Palo Verde Tree Not Blooming . Arizona hosts two native species, the foothills palo verde and the blue palo verde. Why trees fail to bloom. Skies Full of Yellow Blossoms.... Ramblings from a Desert Garden from www.azplantlady.com A handful of ocotillo flowers stand out against a background of blooming palo verde on tanque verde near bear canyon, tucson, ariz., april 13, 2022. And northern mexico.they’re known as a “green stick,” as that is what palo verde means in english. Palo verdes (parkinsonia spp.) bloom during the spring, when the wind is terrible.