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Publication #ENH288

Casuarina spp.: Australian-Pine1

Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean2

Introduction

Long-favored for use in erosion control along beaches, Australian-pine tree is now outlawed in many parts of Florida due to its invasive nature, rapid growth rate, and non-native status. It is not a true pine tree and is not related to the pines. A straight, upright tree capable of reaching 70 to 90 feet in height and possessing rough, fissured, dark gray bark, Australian-pine has what appear to be long, soft, gray green needles but these "needles" are actually multi-jointed branchlets, the true leaves being rather inconspicuous. These "needles" sway gently in the breeze and give off a distinctive, soft whistle when winds are particularly strong. The insignificant flowers are followed by small, spiny cones, less than ½-inch-long.

Figure 1. 

Full Form—Casuarina spp.: Australian-pine


[Click thumbnail to enlarge.]

General Information

Scientific name: Casuarina spp.

Pronunciation: kass-yoo-ar-EYE-nuh species

Common name(s): Australian-pine, casuarina

Family: Casuarinaceae

USDA hardiness zones: 9B through 11 (Figure 2)

Origin: native to Australia, Southeast Asia, and the Pacific Islands

UF/IFAS Invasive Assessment Status: prohibited from use in Florida according to the Federal Noxious Weed List, the Florida Department of Agriculture and Consumer Services (FDACS) 5B-64.011 Prohibited Aquatic Plants, or FDACS 5B-57.007 Noxious Weed List (North, Central, South)

Figure 2. 

Range


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Description

Height: 70 to 90 feet

Spread: 30 to 40 feet

Crown uniformity: irregular

Crown shape: upright/erect

Crown density: open

Growth rate: fast

Texture: fine

Foliage

Leaf arrangement: whorled

Leaf type: simple

Leaf margin: entire

Leaf shape: scale-like

Leaf venation: unknown

Leaf type and persistence: evergreen

Leaf blade length: < 2 inches

Leaf color: gray green

Fall color: no color change

Fall characteristic: not showy

Figure 3. 

Leaf—Casuarina spp.: Australian-pine


[Click thumbnail to enlarge.]

Flower

Flower color: yellow

Flower characteristics: not showy; male—emerges on spikes at the end of the needle-like structure; female—emerges in clusters from leaf axils

Flowering: year-round but most abundant in the spring, and then again in late summer/early fall

Figure 4. 

Flower—Casuarina spp.: Australian-pine


[Click thumbnail to enlarge.]

Fruit

Fruit shape: round, oval; cone-like

Fruit length: < ½ inch

Fruit covering: dry or hard; spiny

Fruit color: brown

Fruit characteristics: does not attract wildlife; not showy; fruit/leaves a litter problem

Fruiting: year-round but most abundant in early summer, and then again in mid winter

Figure 5. 

Fruit—Casuarina spp.: Australian-pine


[Click thumbnail to enlarge.]

Trunk and Branches

Trunk/branches: branches droop; not showy; typically one trunk; no thorns

Bark: dark gray, fissured, and rough

Pruning requirement: needed for strong structure

Breakage: susceptible to breakage

Current year twig color: green

Current year twig thickness: thin, medium

Wood specific gravity: unknown

Figure 6. 

Bark—Casuarina spp.: Australian-pine


Credit:

Gitta Hasing


[Click thumbnail to enlarge.]

Culture

Light requirement: full sun to partial shade

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

Drought tolerance: high

Aerosol salt tolerance: high

Other

Roots: can form large surface roots

Winter interest: no

Outstanding tree: no

Ozone sensitivity: unknown

Verticillium wilt susceptibility: unknown

Pest resistance: resistant to pests/diseases

Use and Management

Highly salt- and drought-tolerant, Australian-pine was widely used in seaside landscapes as a windbreak, screen, clipped hedge, and for topiary. Its ability to withstand heat and other adverse conditions made Australian-pine a favorite for street tree or specimen use also. It is not planted now due to the problems it has created including the elimination of habitat for native plants. Injured trees compartmentalize wounds poorly and decay advances rapidly through the trunk. Old trees which have been topped and abused often become hazardous and they can fall over or drop large limbs.

Growing in full sun or partial shade, Australian-pine will tolerate many adverse conditions, dry or wet soil, heat or high winds. Trees are hardy to about 25°F. Vigorous sprouts often originate from the roots of older trees knocked back by the cold.

Pests

No pests are of major concern.

Diseases

Root rot.

References

Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. Gainesville: 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. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

Footnotes

1.

This document is ENH288, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 1993. Revised 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.


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 UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.