Try growing: mallee eucalypts

Eucalypts, or gum trees, are the quintessential Australian tree, but unfortunately most suburban gardens are not large enough to fit in a full-sized specimen. Majestic trees like the Sydney bluegum and blackbutt are best off growing in the bush or in local reserves.

But you can still have gum trees in your garden, and local ones too, if you choose a mallee rather than a massive forest tree. Mallees are a subset of eucalypts that tend to be relatively short, with multiple stems. They can also be pruned to have a single trunk if that is what you prefer (many nurseries sell them this way).

Species of mallee eucalypt that grow in the Illawarra include:

• Yellow-top mallee ash (Eucalyptus luehmanniana): a stunning mallee with large grey-green leaves with distinctive yellow mid-rib and stalk. In flower it is spectacular. It grows to 5m and prefers skeletal sandstone soil.
• Blue Mountains mallee (Eucalyptus stricta): Pretty mallee with glossy green leaves, to about 3m. Can be seen growing at the top of Mount Keira. Typically multi-stemmed, with trunks around 5-10cm in diameter.
• Narrow-leafed mallee (Eucalyptus apiculata): very similar to the Blue Mountains mallee, but having small, narrow leaves. Grows to 2-3m, with very slender trunks (often no more than 2-3cm in diameter).
• Whipstick mallee ash (Eucalyptus multicaulis): an elegant mallee that grows to 8m, with smooth white or grey bark and long narrow leaves. Grows naturally on skeletal sandstone soil, but can cope with poorer drainage.

Young Eucalyptus luehmanniana waiting to be planted out in our garden. Image by Emma Rooksby. 

A little further north grow a couple of small gum trees that are well suited to Illawarra conditions:

• Dwarf angophora (Angophora hispida): has distinctive new growth, red and covered in fine hairs. Grows to 5-7m.
• Port Jackson mallee (Eucalyptus obstans): typical mallee form with several narrow trunks. Widespread in the Royal National Park, where it grows to 2-3m and looks more like a big shrub than a tree.

An Angophora hispida growing in sandy soil in the Royal National Park. Image by Emma Rooksby. 

Mallees (and some other eucalypt species) have an unusual feature called a lignotuber, which is a lumpy mass at the base of the plant, which can resprout multiple stems after fire or other significant damage. One advantage of this is that, if the tree does grow too tall for your garden, you can simply cut down the trunk, and wait for a new one, or several, to grow. This process, known as coppicing, gives the characteristic ‘mallee look’, and can be useful in managing plants that need to be kept to a limited height.

Port Jackson Mallee (Eucalyptus obstans) - the classic 'mallee look.' Image by Emma Rooksby. 

To give you an idea of what’s possible, our small suburban garden includes nine different species of eucalypt, six of them local mallees, and twenty gum trees in total.

Other resources:

• Gardening Australia program on Eucalypt gardens
• Gardening Australia fact sheet on mallees