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Thrinax morrisii: Key Thatch Palm

Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean

Introduction

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.

Figure 1. Full Form—Leucothrinax morrisii: key thatch palm
Figure 1.  Full Form—Leucothrinax morrisii: key thatch palm

General Information

Scientific name: Leucothrinax morrisii

Pronunciation: loo-ko-THRI-nax more-ISS-ee-eye

Common name(s): key thatch palm

Family: Arecaceae

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

Figure 2. Range
Figure 2.  Range

Description

Height: 20 to 35 feet

Spread: 8 to 12 feet

Crown uniformity: symmetrical

Crown shape: palm, upright/erect

Crown density: open

Growth rate: slow

Texture: coarse

Foliage

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

Figure 3. Leaf—Leucothrinax morrisii: key thatch palm
Figure 3.  Leaf—Leucothrinax morrisii: key thatch palm

Figure 4. Leaf, Underside—Leucothrinax morrisii: key thatch palm
Figure 4.  Leaf, Underside—Leucothrinax morrisii: key thatch palm

Flower

Flower color: white or yellow

Flower characteristics: not showy; emerges in clusters on 3'–5' long, drooping, branched panicles

Flowering: spring and summer

Figure 5. Flower—Leucothrinax morrisii: key thatch palm
Figure 5.  Flower—Leucothrinax morrisii: key thatch palm

Fruit

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

Figure 6. Fruit—Leucothrinax morrisii: key thatch palm
Figure 6.  Fruit—Leucothrinax morrisii: key thatch palm

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

Breakage: resistant

Current year twig color: not applicable

Current year twig thickness:

Wood specific gravity: unknown

Figure 7. Bark—Leucothrinax morrisii: key thatch palm
Figure 7.  Bark—Leucothrinax morrisii: key thatch palm
Credit: Gitta Hasing

Culture

Light requirement: full sun

Soil tolerances: clay; sand; loam; alkaline; acidic; well-drained

Drought tolerance: high

Aerosol salt tolerance: high

Other

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.

Pests

No pests are of major concern.

Diseases

No diseases are of major concern.

Reference

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.

Footnotes

1. This document is ENH-786, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 1993. Revised December 2006 and December 2018. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.
2. Edward F. Gilman, professor emeritus, Environmental Horticulture Department; Dennis G. Watson, former associate professor, Agricultural Engineering Department; Ryan W. Klein, graduate assistant, Environmental Horticulture Department; Andrew K. Koeser, assistant professor, Environmental Horticulture Department, UF/IFAS Gulf Coast Research and Education Center; Deborah R. Hilbert, graduate assistant, Environmental Horticulture Department, GCREC; and Drew C. McLean, biological scientist, Environmental Horticulture Department, GCREC; UF/IFAS Extension, Gainesville, FL 32611.