Fast-growing and appreciating a moist soil, Australian hybrid willow trees traditionally were used as windbreaks and shelter belts in southeastern Australia. Winter deciduous and blooming in early to mid-spring, the flowers aren't particularly showy but produce many seeds. Australian hybrid willows are various hybrids between species Salix matsudana and Salix alba, although they readily cross with other species of willow, too.
Although referred to as "Australian hybrid willow," the initial genetic cross to create it (known botanically as Salix matsudana x alba) occurred in New Zealand according to the National Weed Strategy and Australian Natural Resource Management. Australians call this willow tree the "New Zealand hybrid willow" or "matsudana hybrid willow." In the United States, it is also sold under the trademark name "Austree."
Australians imported nine hybrid willow trees from New Zealand in the 1980s. Three of the trees were considered female, six male. Australian Natural Resource Management comments that at least one of these trees was a natural bisexual plant with both gendered flowers occurring on the same plant. They soon pollinated each other's flowers to reproduce seeds and sprouting willows with a varied set of genes.
Australian hybrid willow is an upright-shaped tree with a narrow oval habit, potentially maturing to heights of 80 feet. Its lance-shaped leaves emerge quite hairy in spring when the pendent catkin flowers appear. Male catkins are larger and more showy, but easily overlooked. The leaves mature light green to pale bluish green and will drop off in winter when cold temperatures or drought sets in. Its bark is fissured and gray-brown.
Australian hybrid willow readily crossbreeds with trees of its species as well as other willow species, particularly with common weeping willow (Salix babylonica) of ornamental gardens. In Australia there is great concern about the trees' invasive spread.
In the United States, the fast growth of Australian hybrid willows makes them a tempting solution to create windbreaks, tall screens or for hillside stabilization. Colorado State University advises gardeners not to embrace these trees since they are not well-suited to seasonal drought and have shallow roots and encroach upon any underground utility that contains moisture. Moreover, willow trees' fast growth makes branches generally weak-wooded and susceptible to damage from strong winds and heavy loads of snow or ice.