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In the Garden: Power of the Purple

By Joan S. Bolton/Contributing Writer

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Jacaranda (jacaranda mimosifolia), also called green ebony, is not only beautiful, but useful, too, as its wood is often harvested to make furniture. / Joan S. Bolton/Contributed

Is there anything more glorious in the garden than a jacaranda tree in bloom?

For sheer impact, a full-grown jacaranda, in its full splendor, is hard to beat. Clusters of literally thousands of lavender, bell-shaped flowers dangle from statuesque branches that reach for the sky.

Adding to the spectacle is that most jacarandas bear their flowers before they leaf out. In neighborhoods lucky enough to have jacarandas as street trees, the June bloom creates a purple haze across the horizon.

By Way of Background

There are about 50 different species of jacarandas native to tropical America. The jacaranda that we know (Jacaranda mimosifolia) is the most widespread of those species, and is native to the dryer parts of Argentina and Brazil. There, it’s known as green ebony and its wood is used in carpentry and to build furniture.

Jacarandas are a popular street tree and park tree worldwide. Pretoria, South Africa, is home to so many jacarandas that it’s known as The Jacaranda City. The trees also bloom spectacularly in Mexico, Israel, Singapore, India and even amid harsh and dry conditions in Nairobi.

In certain areas, including South Africa, Australia and Hawaii, the trees have adapted so completely that they’ve become invasive, crowding out native plants.

In the continental United States, jacarandas flourish in Florida, Texas, Arizona and, of course, California. Horticulturist Kate Sessions of San Diego is credited with introducing the trees to southern California in the early 1900s.

In the Garden

Jacarandas grow relatively fast in the early years. They will eventually reach 25 to 40 feet tall and wide, with their branches forming a dome-shaped canopy. Their gray bark is smooth early on, then becomes fissured with age.

While young, jacarandas can withstand temperatures to about 25 degrees. Over time, they become more cold hardy. But they don’t like cold wind any time of year, and don’t tend to bloom well in cool, coastal, windy areas.

On the Central Coast, you’ll get the best flowering by planting your jacaranda in the hottest location in your garden.

Also, the trees prefer sandy soil, although they’ll tolerate heavier soil as long as it’s well-drained and receives moderate moisture. But don’t over-water. Avoid planting your trees next to or within a lawn, where frequent, shallow sprinkling is the norm.

Instead, provide infrequent, deep soaks. True to the dry conditions of their homeland, a jacaranda’s flowering can be more prolific after a dry winter.

The Cycle

On the Central Coast, jacarandas drop their leaves in spring. Warmer weather toward June brings on the blooms.

As for why random trees leaf out before they flower — some speculate that over-watering encourages the fresh, light-green leaves to appear first.

But I’m not convinced: I’ve seen jacarandas, side by side, where one is bare and blooming and the other is covered in leaves and blooming.

Regardless of when the delicate leaves appear, by summertime they will have filled out, gracefully aligning themselves along gray-colored branches and providing just the right amount of dappled shade.

Blooming continues for a month or two, but never as abundantly as that first wave in June. Meanwhile, round, flat seed pods measuring about 2 inches across will harden, split, then pop open, releasing tiny, winged seeds.

Occasionally, another minor round of flowering occurs in November or December, while the leaves turn a tad yellow.

The trees hang onto those leaves through winter, waiting until spring to let go.

Pruning

Pay attention to your jacaranda’s structure as it matures. Thinning in the early years may be necessary. Branches that are too closely spaced along the main trunk may have weak junctions and break. Remove any sucker growth or obvious, awkward branches that come out at weird angles.

But avoid exacting a technique called lion-tail pruning. That’s when an ill-advised pruner strips all the twigs and leaves off the lower portion of a branch, then leaves the mass at the tip.

The many cuts open up wounds that weaken the branch, and concentrating so much weight at the end of the branch causes the tree to become susceptible to wind damage.

Instead, it is best to remove any errant branches back to the main trunk, leaving the remaining branches evenly spaced throughout the crown.

As time goes you, your jacaranda will develop its own structure and stature, and little or no pruning will be needed.

SEEDS OF WISDOM:

Keep your jacaranda tree away from ponds, fountains, pools and spas. Otherwise, its lovely, lavender flowers and small, delicate leaves can clog filters and pumps, and make quite a mess.

-- JSB

Joan S. Bolton is a local freelance writer and garden designer. She can be contacted through her Web site, www.santabarbara gardens.com.