TREES, PLEASE: Jacarandas: Lovely Lavender or Purple Panic?


By Robin Rivet.

Final exams and Southern California’s rainy season are over, but in June the jacaranda tree (Jacaranda mimosifolia) is just warming up. Some consider it one of the most beautiful species in the world and here in San Diego, it brightens our proverbial June gloom. In fact, the City of San Diego declared it their official city tree.

It’s too bad city architects haven’t figured out how to spec them properly, though. The jacaranda has a tendency to mature from seed like a whip, not producing any side branches when young. This is calamitous in nurseries, mostly because the public is ignorant about what a healthy young sapling should look like. To remedy this “looking-like-a-stick” habit, nurseries typically clip off the tip of seedlings to force bushy, foliar growth atop the whip. It’s an ill-advised practice. If uncorrected, this subjects a tree to a lifetime of weakened branch structure, where six or more leaders originate from the same location at the cut site.

Unfortunately, this contrived look is what the public has come to expect. In fact, many savvy gardeners still succumb to choosing tree specimens with abundant foliar clumps on top. Be smart and avoid this temptation. Instead, seek out seedlings that look like pencils. Grab them, plant them, and watch them flourish. They will grow rapidly and be so happy they were never topped. Eventually, they WILL make branches—when ready. (Keep in mind that this advice is appropriate when selecting trees of most species.)


Street lined with jacarandas in Bryanston, South Africa.

Native to Argentina, jacarandas are now cultivated globally. In California, despite their magnificent, lavender floral display, many residents find the species a colossal nuisance, fraught with long periods of leaf shedding, stretching from March through June. During this semi-dormant time, they sport a bedraggled appearance seemingly at odds with our springtime clocks, especially since northern hemisphere trees already have budded out. Plus, if the dried, ferny leaf accumulations aren’t enough to cause angst, the inevitable free ride indoors of their sticky, oily, purple petals on everyone’s shoes can seal a bad deal. Because of the slippery nature of those fallen flowers, it is not a species well-suited to planting where debris may cause slippage on public walkways. Nevertheless, the jacaranda has naturalized in many Mediterranean climates. In South Africa, its abundant success also threatens native species, and it’s now listed as invasive.

On the other hand, it is really a spectacular tree here, especially when the area under the canopy is coarsely mulched or otherwise landscaped. Fortunately, while many urban trees in San Diego are in decline, jacarandas are gorgeous, hardy, and drought-resistant trees.

Member Robin Rivet is an ISA Certified Arborist, UC Master Gardener, and City of La Mesa Environmental Commissioner. She can be reached at treetutor@gmail.com.


  

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