May Tree of the Month: Jacaranda
By David Gress
Last winter’s late rains and warmer-than-usual temperatures have resulted in the most magnificent display of Jacaranda seen in Santa Barbara for many years - and the fabulous display of vivid, lavender-blue, blooms has occurred much earlier this spring.
Some trees display blooms all across their canopies but have no leaves at all, which makes a spectacular show. Others bear both flowers and light-green, lacy, foliage - a combination that is delightful, whether seen from up close or from afar.
Because it seems to be in exquisite bloom everywhere you look, it is not surprising that Jacaranda is one of the two “Official City Trees” of Santa Barbara (the other is the native Coast Live Oak).
Jacaranda has been widely planted in Santa Barbara since its introduction here in the late 1800’s and - because of its remarkable beauty - more have been planted as street trees in the City than any other tree species.
Jacaranda is so well adapted to Santa Barbara that one might think it is native to California, but it was imported from South America (Argentina and Bolivia). People have been so delighted by this lovely tree that it has been planted in practically every city in the world which has a Mediterranean climate, like ours, or in any other area that is almost frost-free.
The Jacaranda is in the Bignoniaceae, or “Trumpet Flower”, plant family. Its botanical name is Jacaranda mimosifolia. The genus name, Jacaranda, comes from the language of the indigenous people of its native region, and translates as “fragrant”. The species name, mimosifolia, means it has leaves look like those of the Mimosa tree (Albizia julibrissin). It is sometimes commonly known as the “Blue Trumpet Tree” or “Blue Jacaranda”, but most in Santa Barbara just call it “Jacaranda”.
Jacaranda mimosifolia cross pollinates with a related species, Jacaranda acutifolia, and many trees in Santa Barbara appear to be such hybrids, as they have several of the characteristics of this latter species, including a deeper blue bloom color. There is also a white-flowering cultivar, Jacaranda mimosifolia ‘Alba’, that is available in the nursery trade; unfortunately, it is much less vigorous than the true form, perhaps due to the manual grafting necessary to ensure that only white flowers appear.
Jacaranda is a semi-evergreen deciduous tree that carries a rounded crown of dense foliage. In our area, its mature height can be 30 to 45 feet tall with a spread of over 25 feet but, in ideal conditions, it can grow larger; however, it can be easily maintained as a medium-sized tree. Tidy in growth habit, it requires little in the way of pruning, other than removing any dead branches and the occasional vigorous sprout. It can be trained as a low-branched, multiple-trunked, or single-trunked tree.
The Jacaranda blooms over a long period (one to two months, usually May to June), which adds to its appeal. Its lavender-blue flowers occur in thick clusters, or panicles, at the ends of branches. Blooms are 1-1/2 inches long and trumpet shaped. A tree grown from seed can take as long as 5 to 7 years after planting out before its first bloom occurs - and so requires patience – which will be well rewarded. Spent petals fall in great profusion beneath each tree, resulting in an amazing lavender-blue carpet; some folks see this as a lovely bonus, others as a mess!
After pollination, the flowers are followed by flat, round, woody, wavy-edged, seed capsules (up to 2 inches across) that dangle like castanets from the branches. The pods start green in color and turn to brown when mature, producing flat-winged seeds. Trees are easily propagated from seed. The pods are frequently used in dried flower arrangements and in floral decorations.
The Jacaranda’s other outstanding ornamental feature is its delicate fern-like foliage. Its bright green leaves are up to 20 inches in length. They are bipinnately compound, meaning twice-divided. Each mature leaf can have over 1,000 small (¼ inch long) leaflets!
Its light gray to beige bark is smooth when young, becoming checked in small rectangular flakes with age. The light bark color makes a striking contrast with the colorful flowers and with the lush green foliage.
Jacaranda grows best in full sun and in a well-drained loam soil, though it can tolerate poor soils. Once established, it is very drought-tolerant and is cold-hardy to 20 degrees without serious damage. It has few insect or disease problems - but can be plagued with aphids, which can delay and reduce flowering, especially in years with unusually heavy fog.
Jacaranda is admirably adapted for use as a street tree or park tree, for commercial landscapes, and for most home gardens. It is definitely a signature tree in Santa Barbara’s urban forest. It will certainly continue to be planted here, ensuring its place in our community for future generations to enjoy.
Jacaranda can be found all over town - particularly mature street tree specimens can be seen on Carrillo Street (between Santa Barbara Street and Olive Street), on Mission Street (West of Highway 101), on Montecito Street (between Olive Street and Soledad Street), and on Chuparosa Road.
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.
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 to date 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, www.sbbeautiful.org.
Article and Photos by David Gress