The lacy foliage and delicate yellow blossoms of the Parkinsonia aculeata, commonly called the Jerusalem thorn or Mexican palo verde tree, can be seen now in many yards and lining many streets in Redlands.
The genus name Parkinsonia honors British botanist John Parkinson (1567-1650). The specific name means “with spines or prickles.”
A member of the Leguminosae/Fabaceae family — the bean family — the Parkinsonia aculeata is native to the southwestern United States, Mexico, the Caribbean, South America and the Galapagos Islands. Because of its many uses, this multipurpose tree has been introduced in countries including Australia, Cuba, Cyprus, Ethiopia, Guadeloupe, Haiti, India, Indonesia, Israel, Jamaica, Kenya, Martinique, Mozambique, Nigeria, Senegal, Sudan, Tanzania, Uganda, Uruguay and Zanzibar.
The Parkinsonia aculeata is semi-deciduous. It likes Redlands’ full sun, thrives in Redlands’ heat and is very drought tolerant. It has largely done away with leaves that lose water through evaporation and transpiration, producing its food instead within the greenish photosynthetic tissue of the bark.
It is an attractive ornamental tree with unusual wispy foliage that shimmers in a green haze when backlit by sunlight. Throughout the year, showy clusters of vivid yellow almost orchid-like flowers fill the tree like a giant yellow bouquet.
Smooth, light green bark covers the short trunk and graceful, spreading and sometimes weeping branches that are armed with stout, sharp spines. This tree will grow rapidly to about 20 feet in height with an equal spread.
The Mexican palo verde tree likes sandy, alkaline or chalky soils. It makes a fine street or patio tree and provides a delicate, filtered shade.
This tree is well suited to informal landscapes. It can be well used in cactus and succulent gardens where its fine-textured foliage and slender twigs will contrast with the solid blocky shapes of the succulents.
However, be aware that this tree is filled with thorns, it does not do well with lawn watering, it can self-seed and it lives only 15 to 25 years.
The Parkinsonia aculeata is a low-maintenance, attractive tree with its green trunk, unusual leaves and bright yellow flowers. Its weeping form and tiny leaflets make it an interesting bonsai specimen, and its flowering branches can be attractive additions to floral arrangements.
In addition, the Parkinsonia aculeata has other uses. Native Americans harvested the seeds of this tree, sun dried them and used them for food. The fruit pulp and flowers are sweet, and a refreshing drink can be made from the fermented fruits.
Bark, leaves and flowers have been used as herbal medicine for fevers, malaria, digestive problems and other ailments. Leaves and seeds are fed to sheep, goats and livestock.
This tree is also used for firewood, charcoal, timber poles and posts as well as for making paper. This tree has been developed into live impenetrable hedges, fences and windbreaks. It has also been used for soil stabilization, and the leaf litter makes mulch for soils.
Watch for blooming Parkinsonia aculeata throughout Redlands and along freeways. You might even want to add one to your drought-tolerant garden.
For information, call 909-798-9384.
Source: Joyce Dean, a member of the Garden and Floral Arrangers Guild
