Rainbow eucalyptus are native to Indonesia, Papua New Guinea, and the Philippines, but you can also find them in the United States, in places including Hawaii, Florida, and San Diego. (Better Homes & Gardens points out that recent rains have made the trees in San Diego especially colorful this year.)
According to Amusing Planet, the trees’ rainbow coloring happens as bark ages: “[P]atches of outer bark […] are shed annually at different times, showing the bright-green inner bark.
This then darkens and matures to give blue, purple, orange and then maroon tones.”
Rainbow eucalyptus are used for paper, especially in the Philippines, where they are the species most used in pulpwood plantations.
In their natural habitats, rainbow eucalyptus can grow up to 250 feet tall, though in the continental U.S. they stop at around half that size, says Gardening Know How.
If you live in certain parts of the southern U.S. (zones 10 and higher), you may even be able to grow your own, keeping them a manageable size through regular pruning. However, the tree’s roots can cause damage as they grow, so make sure to research first.