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| Common Name: |
Australian Pine, Casuarina, Beefwood |
| Scientific Name: |
Casuarina equisetifolia |
| Hardiness Zone: |
9B through 11 |
| Family: |
Casuarinaceae |
General Information
Australian pine is a deciduous tree with a soft, wispy, pine-like appearance that can grow to 100 feet or more in height. Also known as ironwood, beefwood, she oak and horsetail tree, it bears a superficial resemblance to the conifer genus Pinus because of its small, round, cone-like fruits and its branchlets of scale-like leaves that look like pine needles. This exotic species is not a pine but an angiosperm (flowering plant) that has photosynthetic stems with small whorls of leaves found at the joints of these stems. The native range of the Australian pine is Malaysia, southern Asia, Oceania and Australia; it was introduced in Florida in the late 1800's and planted widely for the purposes of ditch and canal stabilization, shade and lumber. Australian pine is fast-growing (5-10 feet per year), produces dense shade and a thick blanket of leaves and hard, pointed fruits, that completely covers the ground beneath it. Dense thickets of Australian pine displace native dune and beach vegetation, including mangroves and many other resident, beach-adapted species. Because its roots are capable of producing nitrogen through microbial associations, Australian pine can colonize nutrient-poor soils. Once established, it radically alters the light, temperature, and soil chemistry regimes of beach habitats, as it outcompetes and displaces native plant species and destroys habitat for native insects and other wildlife. Chemicals in the leaves of Australian pine may inhibit the growth of other plants underneath it. The ground below Australian pine trees becomes ecologically sterile and lacking in food value for native wildlife. Unlike native shrubbery, the thick, shallow roots of Australian pine make it much more susceptible to blow-over during high wind events, leading to increased beach and dune erosion as well as interference with the nesting activities of sea turtles.
Basic Care
| Bark Characteristics: |
The bark is rough, fissured, and dark gray. It is susceptible to breakage either at the crotch due to poor collar formation, or the wood itself is weak and tends to break. |
| Leaf/Foliage Characteristics: |
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. Leaf teeth (6-8), occasionally brown tipped but usually becoming gradually whiter toward tip and edges. |
| Growth Characteristics |
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-degrees F. Vigorous sprouts often originate from the roots of older trees knocked back by the cold. Casuarina equisetifolia is probably the most invasive species in south Florida; it freely selfseeds in disturbed areas, and once established, may inhibit the growth of native species. It is rarely seen in northern Florida because of its intolerance to long periods of cold weather, but it occurs throughout south Florida (from Orlando south) on sandy shorelines, pinelands, and in the Everglades, above the water table or mean high water line. It frequently colonizes disturbed sites, such as filled wetlands, road shoulders, cleared land, and vacant lots. Although C. equisetifolia doesn't do well in areas of prolonged flooding, it is extremely resistant to salt spray and grows rapidly during hot weather . |
| Flower/Fruit Characteristics: |
Its flowers are tiny, brown and wind-pollinated. The fruit is a nutlet about ½ inch in diameter that contains winged seeds. Fruit characteristics: does not attract wildlife; inconspicuous and not showy; fruit, twigs, or foliage cause significant litter; persistent on the tree. |
| Lighting: |
Full Sun. |
| Watering: |
Young trees need deep watering during dry spells. Established specimens are drought tolerant but will shed branchlets when stressed from lack of water. They don't mind soggy soils and wet feet, but resent prolonged flooding. |
| Feeding: |
Use a well balance fertilizer such as 20-20-20. |
| Pruning/Wiring: |
The tree lends itself to weeping, slanting and cascade styles. As the needles grow longer, pinch them back. Due to the speed with which the tree grows, this pinching can take place as often as once a month. |
| Propagation: |
Seeds, or cuttings of half-ripened wood. |
| Potting: |
Australian Pines can be repotted every 2-3 years, night tempertures should be a minimum of 55 degrees. |
| Pests: |
In Florida, wood borers may attack the Australian Pine. The Lymantriid moth, Lymantria xylina, is one of the worst pests of Casuarina equisetifolia and C. glauca in China (Li e t al. 1981). Ants have been a major source of control in both Puerto Rico and India probably explaining why Casuarina has not over-run Puerto Rico as it has started to do in Florida. Nursery seedlings in India are attacked by Brachytrupes achatinus (cricket), Arbela tetraonis (a bark-eating caterpillar), Coelosterna scabrata (a longicorn) and the grubs of Oryctes rhinoceros (the rhinoceros beetle). . |
| Diseases: |
Blister disease caused by Trichosporium visiculosum Butler is fast spreading and may wipe out Casuarina from Hyderabad and other parts of Andhra Pradesh in India (Begum and Rizwana 1979). This root fungus is encouraged by excessive watering and crowding (Morton 1980). There has been a high rate of root rot in Florida Casuarinas caused by Clitocybe tabescens (Rhoads 1952). This has occurred primarily on higher, well-drained, light sandy soils where oak and other hardwood trees were predominant before clearing. This fungus is known to attack 210 species of plants belonging to 137 genera and 59 families. Stem canker and die-back attributable to the fungus Diplodia natalensis have affected trees in Puerto Rico. |
| Bibliography: |
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. Edward F. Gilman, associate 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. Casuarina equisetifolia, Susan C. Elfers, Global Invasive Species Team, The Nature Conservancy. Australian Pine, Erik Wigert, Wigert's Bonsai Nursery, North Ft Myers, Florida (www.wigertsbonsai.com). |
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