Scientific: Casuarina cunninghamiana (Synonym: Casuarina equisetifolia var. microcarpa)
Common: Australian beefwood, river oak, river she oak, Australian pine
Family: Casuarinaceae
Origin: Australia, northeast Queensland to southeast New South Wales along permanent freshwater streams.
Invasive Alert: Australian beefwood trees are broadly invasive, most notably in South Africa, Florida, and some Pacific Islands. It is not however invasive in the American Desert Southwest.
Pronounciation: Caz-u-RHI-na cun-ning-hay-me-A-na
Hardiness zones
Sunset 8, 9, 12-24
USDA 8-11
Landscape Use: Light shade tree for mesic, oasis, or xeric landscape designs, skyline tree, silhouette tree, roadside, wayside rest stops, urban parks, large residential estates, difficult planting sites.
Form & Character: Upright and weeping, stout and rugged, graceful, conifer like.
Growth Habit: Evergreen, woody, narrowleaf perennial tree, stiffly branched, somewhat pendulous, moderate growth rate to 40- to 70-feet tall with somewhat less than equal spread, main trunk is especially rugged. Mature trees can grow root suckers, though this is uncommon in Phoenix.
Foliage/Texture: Narrow, needle-like leaves, glaucous green to 6-inches long; fine texture.
Flowers & Fruits: Male flowers borne in terminal spikes, to almost 2-inches long, female flowers are small, reddish and oval-shaped; complex fruit structures are cone-like, opening eventually to release samaras (individual wind dispersed fruits).
Seasonal Color: None
Temperature: Tolerant
Light: Full sun
Soil: Tolerant
Watering: In Phoenix, Australian beefwood will require some additional water, but is adaptable to a range of supplemental watering regimes.
Pruning: Train consistently when young to have an upright standard form. As a mature tree, remove deadwood; otherwise, usually little structural pruning (aka crown thinning) is typically needed.
Propagation: Seed
Disease and Pests: None
Additional comments: In Phoenix, this is an uncommon, tough, rugged and highly-adaptable tree that is best used in large landscape spaces such as urban parks or large residential estates. Its relative lack-of-use (bad juju) may be related to its tendency to have a form and character that is somewhat similar in appearance to Tamarix aphylla.
Taxonomic tidbit: The specific epithet cunninghamiana honors Australian botanist Alan Cunningham (1791-1839), who was once the superintendent of the Botanical Gardens in Sydney, Australia.
