In My Garden Blog
April 29, 2004
Southwestern Deserts
By
Cathy Cromell,
Phoenix, AZ
Hybrid palo verde 'Desert Museum' puts on a show of bright yellow bloom.
Palo Verde Trees
Many desert-adapted trees generate glorious clouds of color when in bloom. My favorites, the palo verdes (Cercidium spp.) are finishing up their spring bloom now, dropping a skirt of spent yellow blossoms at their feet. It provides the satisfying equivalent of scuffling through autumn leaves.
Palo verde translates as "green stick" in Spanish, a descriptive reference to the tree's green bark tissue. The smooth green bark is often commented on by desert newcomers who are accustomed to trees with rough, brown or gray bark. Like many desert trees, palo verdes develop a multi-trunked growth pattern that produces a graceful structure and splendid shade canopy.
Palo verde are water-thrify trees in desert landscapes. They require very little water and have developed a mechanism to deal with extended periods of drought by dropping leaves, twigs, and even small branches. The chlorophyll in their green bark allows them to continue photosynthesizing without foliage. Nifty trick!
Varieties
Blue palo verde (C. floridum) is the largest species, growing 30 feet by 30 feet, with a bluish green bark color. To my eyes, it creates the most vivid blast of yellow flowers. Littleleaf or foothills palo verde (C. microphyllum) works better for small yards, growing 15 feet by 15 feet. It blooms later in spring than blue palo verde with less intense color. Palo brea (C. praecox) has a lime-green cast to its trunk. It grows to 25 by 25, with an attractive umbrella-shaped canopy. All are hardy to 15 degrees F, except palo brea which is only hardy to 25 degrees.
Landscape Uses
These trees require no fertilizer and provide great habitat for nesting birds, including hummingbirds. Lower limbs need to be trimmed up gradually over a period of years to produce a canopy that can be walked under. However, they do have thorns so they should be placed where they won't be in the way of frequent foot traffic. There is a thornless hybrid (C. 'Desert Museum') that is a fast grower to 25 feet by 25 feet.
Note: Taxonomists recently reclassified Cercidium to Parkinsonia, but the trees are still labeled in nurseries and public gardens as Cercidium.
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Comments on Palo Verde Trees
We welcome your questions and comments about this column. If
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Mark Charnas
Hi,
My name is Mark Charnas and I live in Northern California. I am
looking for a nursery that would help me purchase a Cercidium
"Desert Museum". Would you have any ideas or resources? My e-mail is
mgcharnas@sbcglobal.net My home phone is (707)526-7847. Thank you
for any assistance you might have to offer.
P.S. I'd be willing to drive to So. Cal.or maybe even Nevada to pick
one up.
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Cathy Cromell
Hi Mark,
These trees are native to the Sonoran and Chihuahuan deserts, so I’m
not sure that it would be the best choice for northern California.
They like aridity, good soil drainage, lots of heat and sunshine,
survive on limited rainfall and are adapted to alkaline soils. They
wouldn’t like roots sitting in wet or cold soil. They are cold hardy
to 15 degrees F. If you think your growing conditions provide that,
I suggest you ask a full-service nursery to contact Mountain States
Wholesale Nursery in Glendale, Arizona. They are well-known
throughout the nursery trade and distribute their plants throughout
the Southwest. Their website is http://www.mswn.com/
If you decide to go ahead, keep me posted on how the tree performs.
Good luck!
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Cathy Cromell
Mark,
A Mountain States Wholesale Nursery rep informs me that there might
be a Desert Museum growing in the Ruth Bancroft garden in Walnut
Creek, California. It has been there only about three years. Also
note that the genus has been changed to Parkinsonia, so you may find
the tree labeled under either that or Cercidium.
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Norma TeBrake
I would like more information on the museum palo verde. We live in
Arizona and are near the Mountain State Nursery you mentioned. Do
you have any better pictures showing this tree full size. I am most
interested in the double trunk.
My email is: intebrake@cox.net
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Cathy Cromell
As noted in that article from 2004, the genus for this tree has been
reclassified and it is now easier to find info under its new name:
Parkinsonia hybrid 'Desert Museum'. You can download an information
sheet from the Mountain States Wholesale Nursery website that also
contains several full size photos at www.mswn.com. A search on
Google Images under the same name comes up with other photos. Note
that Mountain States is wholesale only, so you'd need to buy the
tree from a retail nursery. Good luck!
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