Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean
Introduction
Though commonly called `Black olive tree', this native of the upper Florida Keys (some consider it native, others do not) is not the edible olive we know and love, but does produce a small, black seed-capsule. Black olive is a 40 to 50-foot-tall evergreen tree with a smooth trunk holding up strong, wind-resistant branches, forming a pyramidal shape when young but developing a very dense, full, oval to rounded crown with age. Sometimes the top of the crown will flatten with age, and the tree grows horizontally. The lush, dark green, leathery leaves are two to four inches long and clustered at branch tips, sometimes mixed with the 1/4 to 1 ½-inch-long spines found along the branches.
Figure 1. Full Form - Terminalia buceras: black olive Credit: UF/IFAS
General Information
Scientific name: Terminalia buceras
Pronunciation: ter-mih-NAIL-ee-uh bew-SER-azz
Common name(s): black olive, oxhorn bucida
Family: Combretaceae
USDA hardiness zones: 10B through 11 (Figure 2)
Origin: native to the West Indies
UF/IFAS Invasive Assessment Status: caution, may be recommended but manage to prevent escape (South); Not considered a problem species at this time, may be recommended (North and Central)
Uses: hedge; reclamation; street without sidewalk; shade; specimen; tree lawn 4–6 feet wide; tree lawn > 6 ft wide; urban tolerant; highway median; indoors
Figure 2. Range.
Description
Height: 40 to 50 feet
Spread: 35 to 50 feet
Crown uniformity: irregular
Crown shape: oval, round
Crown density: dense
Growth rate: fast
Texture: fine
Foliage
Leaf arrangement: alternate (Figure 7)
Leaf type: simple
Leaf margin: entire
Leaf shape: obovate, oblanceolate
Leaf venation: brachidodrome, pinnate
Leaf type and persistence: evergreen
Leaf blade length: 2 to 4 inches
Leaf color: dark green on top, paler green underneath
Fall color: no color change
Fall characteristic: not showy
Figure 3. Leaf - Terminalia buceras: black olive Credit: UF/IFAS
Flower
Flower color: creamyyellow to light brown
Flower characteristics: not showy; urn-shaped; emerges in clusters on long spikes
Flowering: spring and summer
Figure 4. Flower - Terminalia buceras: black olive Credit: UF/IFAS
Fruit
Fruit shape: oval
Fruit length: ¼ to ½ inch
Fruit covering: fleshy drupe
Fruit color: black
Fruit characteristics: does not attract wildlife; showy; fruit/leaves a litter problem
Fruiting: ripens mid to late summer
Trunk and Branches
Trunk/branches: branches droop; not showy; typically one trunk; thorns
Bark: brown and smooth, becoming rough and fissured with age
Pruning requirement: needed for strong structure
Breakage: resistant
Current year twig color: gray
Current year twig thickness: thin, medium
Wood specific gravity: unknown
Figure 5. Canopy - Terminalia buceras: black olive Credit: UF/IFAS
Soil tolerances: sand; loam; clay; acidic; alkaline; moist but well-drained
Drought tolerance: high
Aerosol salt tolerance: high
Other
Roots: not a problem
Winter interest: no
Outstanding tree: no
Ozone sensitivity: unknown
Verticillium wilt susceptibility: unknown
Pest resistance: resistant to pests/diseases
Use and Management
The inconspicuous, small, greenish-yellow flowers are produced in 4-inch-long spikes during spring and summer and eventually form the black fruits which, unfortunately, exude a staining tannic acid material which could damage patios, sidewalks, or vehicles parked below. Besides this one drawback, Black olive is beautifully suited as a street, shade, or specimen tree for frost-free areas, but is probably overplanted. There are many native trees which could be used in its place, including satin leaf, gumbo-limbo and others.
Black olive grows slowly and should be planted in full sun or partial shade on well-drained, moist soils. Plants may be slightly damaged at 32°F, but are killed at 25°F. Trees may show chlorosis on high pH soils.
Propagation is by seeds (with difficulty) or layering.
Pests and Diseases
No pests or diseases are of major concern but occasionally bothered by sooty mold and bark borer. Eryphide mites cause galls but no control is needed.
References
Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. University of Florida Institute of Food and Agricultural Sciences.
Koeser, A.K., Friedman, M.H., Hasing, G., Finley, H., Schelb, J. 2017. Trees: South Florida and the Keys. University of Florida Institute of Food and Agricultural Sciences.
