Eucalyptus leucoxylon white ironbark

Eucalyptus leucoxylon in Lasuen Grove, in the Arboretum, near Palm Drive. Sairus Patel, 1 Jun 2015

Eucalyptus leucoxylon flower buds and fruit. John Rawlings, c 2005

The name white ironbark, popular for this species in the U.S., is misleading, for its smooth, thin, peeling bark is a far cry from the persistent, thick, dark covering of true ironbarks such as E. sideroxylon. Much better an epithet is yellow gum. Its creamy trunk can have patches of yellow and gray, with rough unshed bark at the base. Its heartwood, freshly cut, is a pale pinkish buff, strong and durable.

Despite their different bark, yellow gum is closely related to E. sideroxylon, a kinship evident in their reproductive structures: the individual buds, flowers, and fruits are remarkably alike. The outer stamens are sterile, lacking anthers. The buds come in groups of 3 rather than 7 as in E. sideroxylon, though one or two may be missing from a cluster.

Older examples stand at 562 Salvatierra Walk and between Bonair Siding and Maples Pavilion. Others along Pampas Lane opposite the Credit Union date back to the 1960s. These are upright, white-flowered, and can get to considerable height. A solitary specimen featured in the Stanford calendar of May 1981 once stood alone on Maloney Field at El Camino Real (May 2018 street view), but was removed in 2019. 

Subspecies petiolaris, recognized as a distinct species, E. petiolaris, by the Australian Plant Census, is generally a smaller tree with a crooked or sprawling habit and abundant bright red, pink or cream-yellow flowers. The name refers to its stalked (petiolate) seedling and juvenile leaves. Vivid pigmentation often suffuses the branchlets, flower cups, and fruit. Several were planted in the 1960s on both sides of Raimundo Way south of Stanford Avenue, including some scattered behind the magnificent E. cylindrocarpa opposite Wing Place. Then in 1971, more than 130 of the same type were specified along Campus Drive and Escondido Road for the newly built Mirrielees dorm. Many still stand there, especially on the Campus Drive side, including one at the south end with a strikingly swollen lignotuber at its base. Finally, in the 1990s, two dozen more – mostly red-flowered but some white – were planted along Campus Drive to screen the Castaño and Lantana residences. These were also likely E. petiolaris; all were removed by 2020.

Related material: Eucalyptus checklist