Desert Museum palo verde is a fast-growing, drought-tolerant tree that looks like a wonderland when in bloom. But there’s a big problem with these ubiquitous landscape trees. Here’s what you need to know to decide whether this tree would be a good addition to your yard and how to care for an existing one.
Desert Museum palo verde (Parkinsonia X ‘Desert Museum’) is a medium size tree grown for its stunning display of spring flowers, its unique photosynthetic green bark, and for the pleasant dappled shade it provides.
‘Desert Museum’ is a naturally-occurring hybrid of three other palo verde species (blue, Mexican, and foothills palo verdes). It was discovered growing in Tucson. Clones were grown and the rest is history.
It’s often touted as having the best of all three species — thornless, greener bark, longer bloom period, and larger, brighter flowers. Because they are beautiful, low maintenance, and grow fast, they are often planted by builders and in civic spaces.
From April through May, trees are covered with yellow flowers that create a golden carpet when they fall.
As a hybrid of Sonoran and Chihuahuan Desert natives, it’s a resilient tree that survives desert sun and temperature extremes.
When in bloom, Desert Museum palo verde attracts bees and butterflies. These trees also attract attention! The picture above is the street leading into my neighborhood. People from all parts of town come to admire and take pictures of this palo verde lined road.
Things I Like About This Plant
- Jaw-droppingly beautiful when in bloom
- Low water use
- Grows fast
- No thorns, non-toxic
- Attracts bees, butterflies
Why I Do Not Recommend Planting This Tree
This palo verde has been promoted as a highly desirable landscape tree. You would expect a tree named after the renowned Arizona-Sonoran Desert Museum to be exceptional, but it has been a disappointment. This tree has one major flaw that wasn’t discovered until it had already been widely planted.
It grows super-fast, resulting in weak wood and a top-heavy canopy. Consequently, it’s extremely prone to storm damage, often making it a short-lived tree. Trees split apart or lose large branches during monsoon storms or high winds. It’s not unusual for whole trees to be uprooted.
If you’ve ever noticed damaged or fallen trees after a major storm, the victims are often Desert Museum palo verdes.
Arborists called Desert Museum palo verde
a “short-lived, trash tree.” Ouch.
Here’s a downed Desert Museum palo verde in my neighborhood. (We’ve had many.) I was shocked at how small the root system was (3′ across) compared to the size of the tree (25′ tall and wide).
Other Things to Watch Out For
Like other palo verdes, Desert Museum is also prone to palo verde root borer, witches’ broom, and desert mistletoe.
Optimal Growing Conditions
If you’re still thinking of adding a Desert Museum palo verde to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Desert Museum palo verde should be grown in USDA Hardiness Zones 8 – 9. As a hybrid of desert natives, it’s extremely heat tolerant and can withstand temperatures down to 15℉.
Sun Exposure
Desert Museum palo verde thrives in full sun or reflected heat. While it provides beautiful dappled shade, it does not want to be planted in the shade of other trees.
Size and Growth Rate
Desert Museum palo verde grows fast, 8 feet per year the first few years. At that rate, it only takes a few years for plants to reach their mature size of 25 feet high and wide.
Soil
Desert Museum palo verde grows well in any native desert soil — rocky, sandy, or clay — provided it’s well-draining.
Don’t put organic mulch under the canopy of palo verdes, mulch with gravel or decomposed granite instead.
Other Location Considerations
Desert Museum palo verde is a garden friendly tree. It has no thorns and is non-toxic so you can feel comfortable planting it where it might come in contact with people and pets.
However, it’s definitely not litter-free, so don’t put it near a pool or anywhere else you don’t want to deal with showers of flowers in the spring.
These trees are semi-deciduous, and lose their leaves during extreme cold or drought.
Do Palo Verdes Trigger Allergies?
There are a lot of excellent reasons not to plant Desert Museum palo verdes, but their being allergenic is not one of them. Palo verdes and other floriferous plants get the blame for spring time allergies, but they are not a major culprit. Here’s why…
Their flowers evolved to attract pollinators and have sticky, rather than wind-born, pollen. (Ever see a picture of a bee coated with pollen? That’s sticky!) So the pollen is not floating through the air.
Plants with inconspicuous flowers have wind-born pollen. The pollen is usually so small you can’t see it, but it gets up your nose and triggers allergies. Consequently, it’s the plants you’d never suspect that trigger allergies.
In the desert southwest, many highly-allergenic plants including ash, mulberry, juniper, olive, and ragweed put out wind-born pollen the same time that palo verdes bloom. You can get a daily allergy report for your area at Pollen.com.
Desert Museum Palo Verde:
The Essentials
| Common Name | Desert Museum palo verde |
| Scientific Name | Parkinsonia X ‘Desert Museum’ |
| Origin | Sonoran, Chihuahuan Deserts (hybrid) |
| Plant Type | Semi-deciduous tree |
| USDA Zones | Zones 8 – 9 |
| Cold Hardiness | To 15℉ |
| Flower Color | Yellow |
| Flower Season | Spring, summer |
| Mature Size | 25’ high x 25’ wide |
| Growth Rate | Fast |
| Sun Tolerance | Full, reflected sun |
| Water Needs | Low |
| Pests & Diseases | Root rot, borers |
| Garden Friendly | No thorns, non-toxic |
| Cautions | Short-lived, storm damage, root borers, witch’s broom, mistletoe |
| Wildlife | Attracts bees, butterflies |
How to Plant
If you decide to plant one (which I hope you won’t), the rule of thumb when planting any tree in the desert is to dig a hole three times as wide as the root ball but no deeper. Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system.
When to Plant
The best time to plant Desert Museum palo verde is in the fall. This gives your tree three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
Palo verde means “green stick”
referring to the green, photosynthetic bark.
How to Care for Desert Museum Palo Verde
Whether you’ve recently planted a new Desert Museum palo verde or have an existing one in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
Once you’ve got your Desert Museum palo verde in the ground, watering is your most immediate concern. Here is the recommended watering schedule for new trees planted in the spring or fall.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 6 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
After week 8, gradually extend the time between waterings.
How to Water Established Plants
As your tree becomes established, there are two watering factors to consider.
- First is how often to water. This will vary with the seasons.
- Second is how much water to give your tree with each watering. This depends on its current size.
To determine the ideal watering schedule for any desert tree, you’ll find everything you need to know, including easy-to-use charts, at How to Water Desert Trees: How Often? How Much?
Be sure not to overwater. These plants survive just fine in the wild without irrigation. Too much water results in a weaker tree that is more prone to storm damage.
If you have a tree on irrigation, be sure to water at the drip line. Most homeowners never move their emitters beyond the trunk, which discourages roots from growing wide.
Should You Fertilize?
There is no need to fertilize palo verdes which evolved to grow in desert soil. And since this tree is a member of the legume family (Fabaceae), it fixes nitrogen, which naturally improves the surrounding soil.
How to Prune
While I always recommend having an arborist (not a so-called “landscaper”) prune your trees, it’s particularly important that you have your desert museum palo verde properly pruned to minimize storm damage.
Trying to save money by not pruning or doing it yourself could result in an easily damaged, short-lived tree.
Plant Lover Facts
Desert Museum palo verde (Parkinsonia X ‘Desert Museum’) is unusual in that it’s a naturally occurring hybrid of a hybrid.
It was discovered by Mark Dimmitt, PhD, the Arizona-Sonoran Desert Museum’s Director of Natural History at the time. He noticed some different-looking palo verdes in the wild, and started cultivating one that eventually became the parent for the tree now known as the Desert Museum palo verde.
It was determined to be a cross between a blue palo verde (Parkinsonia florida) and a hybrid tree that was a cross between foothills palo verde (P. microphylla) and Mexican palo verde (P. aculeata).
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for over 15 years.
Photo Credit
Megalibrarygirl, CC BY-SA 4.0, via Wikimedia Commons