• Shelby Pietersen

What you need to know about Blue Gum Trees

Blue Gum Trees, scientifically known as Eucalyptus Globulus, are some of the most controversial trees in South Africa. You can find a cluster of these trees almost anywhere you look in the Western Cape. Where there is one Blue Gum Tree you can always expect to find many.


Blue Gums were introduced in the late 1800s from New South Wales, Victoria, and Tasmania. It would be an understatement to say that they grew deep roots in the Western Cape.


There are over 300 species of Eucalyptus trees in Southern Africa including Blue Gum, Flowering Gums, Red River Gums, Penny Gums, and Silver Stringy Bark Gums. These gums have been helpful for South Africa commercially as the trees are used for poles and lumber, firewood, and as shade and a food source for honey bees in the agricultural areas of the Western Cape and the Overberg.


Here are some fun facts about Blue Gums:

  • There are over 300 species of Eucalyptus trees that have been introduced to southern Africa.

  • The trees have been a positive asset for South Africa’s forestry industry.

  • They are called gum trees because of the tree sap they release.

  • Blue Gum trees are used for lumbar, as shade for honey bees in the farmlands, and as slow-burning firewood.

Why Blue Gums are considered invasive and detrimental

  • Alelopaphy on ground veg and negative impact on biodiversity

  • Exhausts soil from nutrients

  • Leaves contain natural oils and over time the leaves accumulating on the ground can lead to fire hazards

  • Extremely water heavy

  • Compromised root systems are common and the trees can become top-heavy and pose threats to surrounding structures.

  • They thrive in the western cape’s climate and propagation is so fast and easy that it can drown out the indigenous flora

What to do about the Blue Gums in your garden

  • Don’t plant grass or vegetables or other trees close to or under Blue Gums, they will struggle to thrive.

  • Plant succulents instead

  • Remove any dangerous or decaying limbs or the entire tree safely,

  • Top pruning of the Blue Gum causes the tree to grow lower and denser.

If you would like professional advice on how to care for or remove the Blue Gums in your garden, contact Overberg Arborists.

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