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Publication #ENH-786

Thrinax morrisii: Key Thatch Palm1

Edward F. Gilman and Dennis G. Watson2

Introduction

This native North American palm slowly grows 20 to 30 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 spring flowers are followed by small, round, fleshy white fruits.

Figure 1. 

Middle-aged Thrinax morrisii: Key Thatch Palm

General Information

Scientific name: Thrinax morrisii
Pronunciation: THRY-nacks more-ISS-ee-eye
Common name(s): Key Thatch Palm
Family: Arecaceae
USDA hardiness zones: 10B through 11 (Fig. 2)
Origin: native to North America
Invasive potential: little invasive potential
Uses: deck or patio; container or planter; specimen; highway median
Availability: somewhat available, may have to go out of the region to find the tree

Figure 2. 

Range

Description

Height: 15 to 20 feet
Spread: 6 to 10 feet
Crown uniformity: symmetrical
Crown shape: palm, upright/erect
Crown density: open
Growth rate: slow
Texture: coarse

Foliage

Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: entire
Leaf shape: star-shaped
Leaf venation: palmate
Leaf type and persistence: broadleaf evergreen, evergreen
Leaf blade length: 18 to 36 inches
Leaf color: green, blue or blue-green
Fall color: no color change
Fall characteristic: not showy

Flower

Flower color: white/cream/gray
Flower characteristics: not showy

Fruit

Fruit shape: round
Fruit length: less than .5 inch
Fruit covering: fleshy
Fruit color: white/gray
Fruit characteristics: does not attract wildlife; showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; not showy; typically one trunk; thorns
Pruning requirement: little required
Breakage: resistant
Current year twig color: not applicable
Current year twig thickness:
Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun or partial shade
Soil tolerances: clay; sand; loam; alkaline; acidic; occasionally wet; 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 Thatchpalm 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.

Footnotes

1.

This document is ENH-786, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November 1993. Revised December 2006. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.

2.

Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, associate professor, Agricultural Engineering Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.