Lessons Learned from Irma – Postscript

As a follow-up to last week’s article, Richard Lyons’ Nursery would like to make a couple of additional recommendations in the wake of Hurricane Irma:

As to palms, plant more. As to Ficus benjamina, plant fewer.

Palms appear to have weathered Irma quite well in comparison to broadleaf trees. The explanation in most cases is their architecture. Single-trunked species in particular present a relatively slender profile in the face of strong winds. Even the tall-growing Royal Palm is quite resistant to hurricanes. Longtime observers of tropical weather know that only the strongest hurricanes knock Royal Palms down in any quantity. The key to their success is that they not only bear a small number of leaves, but those leaves snap off in fierce winds, leaving a figurative pencil in the landscape. Similarly, other palm genera which hold a limited number of leaves – such as Veitchia, Chambeyronia, and Satakentia – had a high survival rate versus Irma.

Ficus benjamina, on the other hand, performed miserably. There are lots of ficus species in the world – upwards of 800 – and many are worth having in the landscape of southern Florida, but the widespread use of Ficus benjamina has become quite questionable. It’s an understatement to say that this species comes with a lot of baggage. First, the tree’s very form is an invitation to demolition via wind, even just gusts from a heavy thunderstorm. The crown is not only broad, but extremely dense. Consequently, it doesn’t allow strong breezes to pass through, instead putting up resistance that often yields bad results.

The execrable practice of hatracking, now illegal in many municipalities, certainly reduces canopy in the short run, but fails in the long run because new growth creates an even denser crown. A superior technique, selective pruning, also known as pick-pruning, can succeed in opening up the crown of F. benjamina by removing entire branches, but it is a labor-intensive endeavor. The U.S. Forest Service has gone on record since at least 1993 discouraging the use of this species in residential settings.

Second, the root system of F. benjamina is notoriously aggressive, capable of heaving not only sidewalks, but also foundations and even interior floor finishes such as terrazzo. The limestone substrate in much of Miami-Dade County further exacerbates the problem by confining the root system to a shallow zone. When a specimen of F. benjamina falls, its root system can lift a mass of sod, soil and rocks 12 ft. or more into the air.

Third, the plant’s aerial roots are both a blessing and a curse. They have a purpose: Upon touching the soil they form a new trunk that helps stabilize the tree. But that trait also permits the tree to enlarge to dimensions unsuitable to most home landscapes. When owners cut the roots above ground to control the tree’s spread, they also destabilize it.

There is no denying the allure of F. benjamina as an ornamental plant; its use has long distinguished the roadways of Coral Gables. But even the City Beautiful recognized the maintenance demands and risks associated with the species. In recent years, it has been replacing F. benjamina with Live Oak, a species more amenable to sculptural pruning, less demanding of maintenance, and more capable of withstanding tropical storms.

 

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