Rainbow Eucalyptus: The World’s Most Colorful Tree

Bark is the tree’s protective outer layer. It acts like natural armour, shielding the inner living tissues from:

Extreme temperatures
Insects and fungi
Mechanical damage
Water loss

Scientifically, bark consists of all tissues outside the vascular cambium (the growth layer that produces new wood and phloem). It includes:

Phloem – transports sugars from leaves to the rest of the tree
Cork cambium (phellogen) – produces protective cells
Cork (phellem) – the outermost dead protective layer

As trees grow, bark continuously forms from the inside while older layers die and crack or peel away. In most species, this produces rough, thick, brown bark. But in one extraordinary species, this natural process creates a living rainbow.

The Rainbow Eucalyptus (scientific name: Eucalyptus deglupta) is the only eucalyptus species naturally found in the Northern Hemisphere. It is famous for its multicoloured bark that looks almost painted by hand.

Why is it so Colourful?

The bark of the Rainbow Eucalyptus is very thin and smooth, unlike the thick bark of many other trees. As the tree grows:

The outer bark layer peels away in strips.
Fresh inner bark is exposed — bright green at first.
As this new bark matures, it gradually changes colour:
- Green → Blue → Purple → Orange → Reddish-brown

Because different sections peel at different times, multiple colours appear simultaneously, creating the iconic rainbow effect.

Scientists believe the colours result from chemical changes in tannins and pigments as the bark oxidises and matures.

Interestingly, some researchers suggest that the striking colouration may help protect the tree, possibly by confusing insects or deterring parasites, but there is no confirmed scientific evidence yet. The protective function of the colours remains an open question.

How Big Does Rainbow Eucalyptus Grow?

This is not just a beautiful tree, it’s a giant.

Height: up to 75 meters (246 feet)
Trunk: tall, straight, and column-like
Growth rate: extremely fast in tropical climates

In optimal rainforest conditions, it can reach impressive heights within just a few decades. Standing next to one feels like being at the base of a painted skyscraper.

Rainbow Eucalyptus is native to the Philippines, Indonesia and Papua New Guinea. However, it has been planted in other tropical regions around the world.