Thrinax morrisii: Key Thatch Palm1
This native North American palm slowly grows 20 to 35 feet tall, its smooth, slender trunk topped with 3.5-foot-wide, beautiful, green and silver fronds. The fronds are a shimmering silver/white underneath and are a source for thatch. The insignificant white or yellow spring flowers are followed by small, round, fleshy white or yellow fruits.
Scientific name: Leucothrinax morrisii
Pronunciation: loo-ko-THRI-nax more-ISS-ee-eye
Common name(s): key thatch palm
USDA hardiness zones: 10B through 11 (Figure 2)
Origin: native to Florida and the West Indies
UF/IFAS Invasive Assessment Status: native
Uses: deck or patio; container or planter; specimen; highway median
Height: 20 to 35 feet
Spread: 8 to 12 feet
Crown uniformity: symmetrical
Crown shape: palm, upright/erect
Crown density: open
Growth rate: slow
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: entire
Leaf shape: fan-shaped
Leaf venation: palmate
Leaf type and persistence: broadleaf evergreen, evergreen
Leaf blade length: 18 to 24 inches
Leaf color: dark green to blue and shiny on top, silver to light green underneath
Fall color: no color change
Fall characteristic: not showy
Flower color: white or yellow
Flower characteristics: not showy; emerges in clusters on 3'–5' long, drooping, branched panicles
Flowering: spring and summer
Fruit shape: round
Fruit length: ¼ to ½ inch
Fruit covering: fleshy
Fruit color: turns from white to yellow when ripe
Fruit characteristics: does not attract wildlife; showy; fruit/leaves not a litter problem
Fruiting: spring to fall
Trunk and Branches
Trunk/branches: branches don't droop; not showy; typically one trunk; no thorns
Bark: light gray and smooth, often with remnant leaf bases and fibers just below the crown
Pruning requirement: little required
Current year twig color: not applicable
Current year twig thickness:
Wood specific gravity: unknown
Light requirement: full sun
Soil tolerances: clay; sand; loam; alkaline; acidic; well-drained
Drought tolerance: high
Aerosol salt tolerance: high
Roots: not a problem
Winter interest: no
Outstanding tree: yes
Ozone sensitivity: unknown
Verticillium wilt susceptibility: resistant
Pest resistance: free of serious pests and diseases
Use and Management
This palm is small enough to be popular in residential landscapes. It is often planted as a single specimen or in groups of three to accent an area. Due to the coarse texture, they make a nice entryway palm planted to attract attention to the front door of a building. It often looks best planted in a mulched area or in a bed with a low-growing ground cover.
Key thatch palm should be grown in full sun or partial shade and is highly drought- and salt-tolerant, making it ideal for seaside applications.
Propagation is by seed.
No pests are of major concern.
No diseases are of major concern.
Koeser, A.K., Friedman, M.H., Hasing, G., Finley, H., Schelb, J. 2017. Trees: South Florida and the Keys. Gainesville: University of Florida Institute of Food and Agricultural Sciences.