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Publication #ENH-163

Acacia auriculiformis: Earleaf Acacia1

Edward F. Gilman and Dennis G. Watson2

Introduction

Quickly reaching a height of 40 feet and a spread of 25 feet, Earleaf Acacia becomes a loose, rounded, evergreen, open shade tree. It is often planted for its abundance of small, beautiful, bright yellow flowers and fast growth. The flattened, curved branchlets, which look like leaves, are joined by twisted, brown, ear-shaped seed pods. Growing 6 to 8 feet per year, Earleaf Acacia quickly grows into a medium-sized shade tree. This makes it a popular tree. However, it has brittle wood and weak branch crotches, and the tree can be badly damaged during wind storms. Prune branches so there is a wide angle of attachment to help them from splitting from the tree. Also be sure to keep the major branches pruned back so they stay less than half the diameter of the trunk. These techniques might increase the longevity of existing trees.

Figure 1. 

Mature Acacia auriculiformis: Earleaf Acacia

General Information

Scientific name: Acacia auriculiformis
Pronunciation: uh-KAY-shuh ah-rick-yoo-lih-FOR-miss
Common name(s): Earleaf Acacia
Family: Leguminosae
USDA hardiness zones: 10A through 11 (Fig. 2)
Origin: not native to North America
Invasive potential: According to the IFAS Assessment of the Status of Non-Native Plants in Florida's Natural Areas (Fox et al. 2005), Acacia auriculiformis (earleaf acacia) may be used with caution in the central and southern zones of Florida, but should be managed to prevent its escape (counties are listed by zone at: http://plants.ifas.ufl.edu/assessment ); and is not considered a problem species and may be used in north Florida.
Uses:
Availability: somewhat available, may have to go out of the region to find the tree

Figure 2. 

Range

Description

Height: 35 to 40 feet
Spread: 25 to 35 feet
Crown uniformity: irregular
Crown shape: round
Crown density: moderate
Growth rate: fast
Texture: medium

Foliage

Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: entire
Leaf shape: linear
Leaf venation: parallel
Leaf type and persistence: evergreen, broadleaf evergreen
Leaf blade length: 4 to 8 inches
Leaf color: green
Fall color: no color change
Fall characteristic: not showy

Flower

Flower color: yellow
Flower characteristics: showy

Fruit

Fruit shape: irregular
Fruit length: 1 to 3 inches
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: does not attract wildlife; showy; fruit/leaves a litter problem

Trunk and Branches

Trunk/bark/branches: branches droop; not showy; typically one trunk; thorns
Pruning requirement: needed for strong structure
Breakage: susceptible to breakage
Current year twig color: green
Current year twig thickness: thin
Wood specific gravity: unknown

Culture

Light requirement: full sun
Soil tolerances: clay; sand; loam; alkaline; acidic; occasionally wet; well-drained
Drought tolerance: high
Aerosol salt tolerance: moderate

Other

Roots: not a problem
Winter interest: no
Outstanding tree: no
Ozone sensitivity: unknown
Verticillium wilt susceptibility: resistant
Pest resistance: free of serious pests and diseases

Figure 3. 

Foliage

Use and Management

Seeds also germinate in the landscape and it has escaped cultivation in south Florida where it is becoming a mildly invasive weed in some areas. However, it is not as invasive as Australian pine or Brazilian pepper and probably will not become so. For these reasons, many people consider this to be an undesirable tree.

Earleaf Acacia grows in full sun on almost any soil including alkaline and is moderately salt-tolerant. It will withstand periods of water inundation but is also very tolerant of drought.

Pests and Diseases

No pests or diseases are of major concern. Occasionally anthracnose infects leaves.

Footnotes

1.

This document is ENH-163, 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 April 2007. 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.