Desert Museum Palo Verde ~ Flowering Fools

Parkinsonia x 'Desert Museum'

Here it is, late November, and the Desert Museum Palo Verde (Parkinsonia x ‘Desert Museum’) trees are flowering again. Flowering normally occurs in early to late spring. Although ‘Desert Museum’ has a longer bloom period than many Parkinsonia species and hybrids, flowering this late is unusual. My trees still receive regular watering. That, plus unseasonably warm weather, may be contributing to this very late showing.

Although I usually follow good cultural practices in my garden, I will admit to over watering my trees to attain maximum growth in a short time. This is not a good practice. It causes shallow roots and weak branches from too rapid growth. The rapid growth then makes frequent pruning necessary to thin and maintain shape. I’ve had numerous over watering problems with all the other tree varieties in my garden, but the Desert Museum Palo Verde trees have sailed through wind and rain and excessive pruning with nary a broken branch or uprooting. (I did have a large branch that split from excessive weight during a heavy spring flowering, but I bolted and braced it, and within a year, it was good as new.)

I have a theory as to why the Desert Museum Palo Verde trees have done so well even with the rapid growth. I placed all four on contoured mounds of dirt formed to give my garden the natural desert look of small hills and depressions. These mounds are three feet higher than the rest the ground, and about twelve feet long. Since the new mounds have loose soil compared to normal hard desert soil, water is able to move downward quickly. This means the roots of the Palo Verde trees grow deeper than the other trees that are on level ground. Just a theory--can't prove it.

I am going to start weaning the trees from supplemental water starting in December. After about nine months, only an occasional summer watering will be necessary. So, it's probably goodbye to future November flowers.