Trees of Australia Flooded Gum

The term ‘flooded gum’ can refer to several species of eucalyptus.  Probably the most common reference is to Eucalyptus grandis, also known as the Rose Gum. It is a large, fast-growing hardwood which prefers deep, well-drained soils.  The name ‘rose gum’ comes from the attractive pink heartwood. 

The rose gum is the most widely planted eucalyptus species. It is native to the coastal areas from Newcastle, New South Wales northwards into northern Queensland. It tends to be found mostly in moist valleys. Its uses include saw-milling, timber production, ornamental and shade. Timber production includes decking, flooring, furniture and joinery as well as general construction. It is also one of the species acceptable as browse for koalas. It is a tall tree rising to around 40 to 50 metres and has a straight trunk. A stocking of rough, flaky bark covers the lower few metres of the trunk. The trunk then rises smoothly, ranging in colour from white to grey-white or blue-grey. 

It is quite similar in appearance to the Sydney Blue Gum. It is very fast growing. Rates of 7.5 metres of growth in the first year have been recorded under plantation situations and 3 metres annual growth rate under natural conditions.  It is frost tolerant and has white flowers. The heartwood ranges in colour from pale pink to a reddish brown. The sapwood is usually paler in colour.  The grain is straight with a moderate coarse but even texture. When freshly planed, the timber has an attractive sheen. The grain often reflects the passage of the scribbly borer, an insect which leaves a small trail mark in a ‘scribbling’ pattern.  Slight fraying may occur when cutting the timber. Use of the heartwood is limited as it is only moderately durable. 

Eucalyptus urophyalla is a hybrid of the species which is being cultivated extensively in Brazil.  South Africa and Malaysia are also utilising Eucalyptus urophyalla. The Western Australian flooded gum, Eucalyptus rudis, is found from Eneabba to Margaret River and east to the Pallinup River. It occurs in a wide variety of soil types provided there is sufficient moisture for its needs.  It is suited to poorly drained areas. 

Like eucalyptus grandis, it fringes watercourses and swamps. It is a bluish-tinged tree with woody fruits. The fruits are hemispherical to broadly bell-shaped, and divided into several compartments, each opening by a small valve.  It is a medium sized tree growing up to 20 metres high with rough grey bark on the lower trunk and smooth grey bark on the branches.  The leaves are between 80 and 140mm long. The upper surfaces are dull to shiny green and the lower surfaces may be paler. The inconspicuous white flowers are borne from September to November.  It is common to find scale insects infesting the flooded gum.  The insects and the sugary, waxy scales produced by the insects were all once eaten by the aborigines of the area.