Palo verde (Parkinsonia or formerly Cercidium) is a genus of flowering deciduous trees that originate from the pea family (Fabaceae).
There are over ten species that all have their origins in semi-desert landscapes, many from the Americas.
If you're looking for a tree that will grow in dry, hot, and infertile environments, has interesting bark color, and produces bright flowers, then one of the palo verde species could be a good fit. They're regarded as some of the most drought-tolerant trees around and are perfect for xeriscape landscaping.
When they receive enough water, palo verde, tend to have a thin, upright form with feather-like, pinnate foliage and thorny branches. Without water, they have a lower, shrub-like, and wide-spreading appearance.
The abundant spring flowers are usually a bright yellow, but can also be white, and their nectar is specifically attractive to the pallid bee species in the United States.
The fallen flowers can be rather messy, and it isn't recommended to plant them where the canopy will overhang outdoor swimming pools for this reason.
The name palo verde in Spanish means "green stick", and this name is derived from the trunk of the tree which is usually a shade of green.
These trees are considered drought-deciduous and drop their leaves when they go long periods without water. They're unique as their trunks are capable of performing photosynthesis, rather than just through the leaves.
Two of the most widely recognized of these trees in North America are the blue palo verde (Parkinsonia florida) and the Mexican palo verde (Parkinsonia aculeata).
Caring for Palo Verde Trees can vary depending on the species you opt for. Still, the general care information outlined below will be a useful guide as to whether you can provide the right conditions and maintenance levels.
As you would expect from a desert-thriving species, palo verde trees benefit from growing in a full sun position.
Palo verde trees aren't particular about soil types, as long as it's well-drained. They won't tolerate soggy conditions.
Palo verde trees, once established, are incredibly drought tolerant. They can survive with little to no water for prolonged periods during the hot and dry seasons.
Without water, they're slower growing and tend to remain more shrub-like. If they receive more regular watering, however, they'll have a more upright and attractive form, and their foliage and flowering will be denser.
Temperature and Humidity
It won't come as any surprise that palo verde trees thrive in hot and dry regions. They don't appreciate too much humidity and are cold hardy down to around 15 degrees Fahrenheit.
Established palo verde trees generally don't need any fertilizing.
Palo Verde Varieties
Below are a few of the most common Palo Verde species found across North America.
- Blue palo verde (Parkinsonia florida) - this popular tree is taller and more upright than most other Parkinsonia species; it can grow over 30 feet tall. It's also fast-growing, matures quickly, and, as the name suggests, it has a more bluish-green hue to its trunk and branches. This species prefers finer soil and tolerates more water. Unlike many palo verde, it can even grow in lawn conditions.
- Foothill palo verde (Parkinsonia microphylla) - one of the slowest growing palo verde species, they have the least tolerance for wet conditions. Their pale yellow flowers aren't as abundant as other species, and they don't bloom for as long either.
- Mexican palo verde (Parkinsonia aculeata) - this is one of the most well-known species, but, these days, it isn't the most popular choice. It's fast-growing and self-seeds the most readily, meaning new trees can sprout up in unwanted places if care is not taken.
- 'Desert Museum' - this cultivar is a hybrid cross of P. aculeata x P. microphylla x P. florida. It's known for being thornless, having an upright growth habit, and for producing an abundance of bright yellow flowers over a long period during the spring, while not generating a lot of messy litter.
Propagating Palo Verde
Palo verde trees need to be propagated from seeds rather than cuttings.
The seeds will benefit from being carefully scarified and then soaked in hot water overnight before immediately sowing them.
The seeds will need to be kept moist, warm, and lightly shaded while germinating. It usually only takes around two weeks for seedlings to appear.
Palo verde trees benefit from pruning of their low branches during warm weather while they're establishing to raise the canopy and promote a more upright form.