May Tree of the Month: Blue Hesper Palm

As if the Blue Hesper Palm’s stunning bluish-gray fronds weren’t enough to make this palm stand out in any landscape, its long arching inflorescences are so incredible that they force you to stop and gaze in amazement.

It is no wonder that this hardy palm has been a favorite of exotic plant collectors and garden enthusiasts around the world, earning it the prestigious Award of Garden Merit from the Royal Horticultural Society in the UK.

In 1865, nurserymen in Santa Barbara recognized its extraordinary ornamental value and introduced it to our area – where it has been planted and admired ever since.

The Blue Hesper Palm is native to Baja California, Mexico. It is found in the rocky canyons and washes, often growing alongside the much taller common Mexican Fan Palm, Washingtonia robusta. In its native habitat, it can reach heights of 50+ feet over the course of its lifetime of more than 200 years. Locally, where it grows very slowly due to our lower temperatures, it is rare to find these trees over 20 feet tall.

At the apex of its solitary trunk, distinctive bluish-gray fronds sprout and grow to become 3- to 6- feet in width and stand at the end of 3 to 4 feet long petioles (stems). Caveat: the petioles are armed with yellowish, rather nasty, hooked teeth. The surprisingly stiff fronds are costapalmate (shaped like a human palm but with a definite midrib, an extension of the petiole into the frond) and are deeply divided into 40 to 60 segments. On the trunk beneath the newer fronds, older fronds dry up but persist (remain attached). These form a shaggy “skirt” unless pruned off. The trunk is stout and gray colored.

From March to July, spectacular inflorescences (flower-bearing stems) appear from between the fronds, extending out in long arches that grow to 12- to 16-feet in length, often touching the ground! Each stem has branches with hanging strands that contain literally thousands of creamy white flowers. The very small, 3-petaled, fleshy flowers are monoecious (each flower containing both male and female flower parts) and usually bloom in clusters of three.

After pollination, the fruits that develop are round, ¾- to 1-inch in diameter, and are first green in color, then turn to yellow and, finally, to brownish-black. The Cocopah, a people native to Baja California, gathered the fruit and ate the nutritious seeds roasted.

Its common name, “Blue Hesper Palm”, refers to the Greek name of the “Hesperides”, mythological nymphs who tended their magical garden in the far western lands of the world, and probably was given to this palm because it is native to the west coast of Mexico. Its many other common names relate to the color of its foliage: “Gray Goddess Blue Palm”; “Blue Fan Palm”; and “Mexican Blue Palm”.

The botanic name for Blue Hesper Palm is Brahea armata. The genus name, Brahea, honors the 16th—17th-century Dutch astronomer, Tyco Brahe. The specific epithet, armata, refers to its armor of barbed petioles.

Because it is slow-growing, this lovely palm can easily fit into most gardens and landscapes. It grows and looks best in full sun but can tolerate partial shade. It is quite drought-tolerant but is more robust and grows faster with occasional deep water in the dry months. It can tolerate almost any type of soil but should have good drainage. Note that its roots are extremely sensitive to disturbance when transplanting. It is cold hardy, surviving temperatures to 10 degrees Fahrenheit, which explains how it will grow, remarkedly, as far north as England.

The Blue Hesper Palm adds a striking contrast and focal point in gardens and landscapes. Mature specimens can be seen in Alice Keck Park Memorial Garden (along Micheltorena Street), in Chase Palm Park (north of Cabrillo Boulevard), at the County Courthouse (east of the sunken garden), and in front of the Cabrillo Arts Pavillion. Not surprisingly, many are planted in the “Blue Garden” at Lotusland.

Tree-of-the-Month articles are sponsored by Santa Barbara Beautiful, whose many missions include the increase of public awareness and appreciation of Santa Barbara’s many outstanding trees and, in a long-time partnership with the City Parks & Recreation Department, the funding and planting of trees along the City’s streets – a project which has resulted in the planting, to date, of more than 12,000 street trees.

Those who wish to honor a special someone can do so with an attractive commemorative marker that will be installed at the base of an existing street tree in the City of Santa Barbara. Because Santa Barbara Beautiful has participated in the planting of over 13,000 street trees, there are plenty of trees from which to choose! Application forms are available on the Santa Barbara Beautiful website.