How to Grow a Rainbow Eucalyptus – Your Very Own “Graffiti Tree”

Your first reaction to seeing a rainbow eucalyptus tree might be outrage: “How could some kids paint all over the trunk of that beautiful tree!” But look a little closer and you’ll realize all those red, green, orange, purple-brown, and yellow stripes that look like graffiti are natural. The tree’s smooth bark sheds in strips, leaving behind these brilliant, almost psychedelic colors. Known by the scientific name eucalyptus delgupta, this unique, beautiful species thrives outdoors in tropical climates. But even if you live in a frost-prone part of the world, you can enjoy your very own “graffiti tree” in a pot. Read on to find out how to grow a rainbow eucalyptus outdoors or indoors, depending on your climate.

Description of the Rainbow Eucalyptus

The bark of a rainbow eucalyptus makes it look like a species from another planet!

Origin and Uses

Eucalyptus deglupta is known not only as the rainbow eucalyptus but as the Mindanao gum or rainbow gum tree. It grows naturally in the tropical climates of Indonesia, Papua New Guinea, and the Philippines. It is the only species of eucalyptus that grows in the rainforest. Commercially, it is a valuable crop in the Philippines for manufacturing paper (ironically, white paper!). In frost-free climates around the world, it is a prized ornamental tree for botanical gardens or private homes.

Size

This species grows 3-5 feet a year and reaches enormous size. Mature specimens develop trunks up to 8 feet in diameter and can reach 100-246 feet tall. To put that in perspective, the room ceiling height in many suburban homes is 8 feet, and 246 feet is about as tall as a 23-story building.

Blooms and Seeds

The tree produces clusters of yellow and white blooms that look a bit like pom-poms or sea anemones. Fertilized, these produce small multi-chambered capsules that release 3-12 tiny brown, winged seeds.

Color

Of course, the tree’s most memorable feature is its bark. As it sheds, it leaves behind bare spots on the trunk in astonishingly bright shades of green, orange, yellow, red, and purple-brown. Even the leaves have some color, being bright red or pink when they’re new and turning reddish again when they’re old. Pictures really can’t compare to seeing one of these otherworldly-looking trees in person.

Conservation Status of the Rainbow Eucalyptus

As the species has been harvested and rainforests cleared, its native habitat has become fragmented. Experts estimate the population of these trees has decreased by about 30% over the past two centuries. The IUCN has designated the rainbow eucalyptus as a vulnerable species. Honestly, it’s hard to imagine such a treasured species going completely extinct. They are represented in specimens around the world and could be easily replanted and grown into forests on protected land. However, such a controlled environment is a far cry from the spectacular beauty of these towering trees in the wild in a diversified tropical jungle ecosystem.

Growing a Rainbow Eucalyptus Outdoors

Rainbow eucalyptus trees grow in hardiness zones 10-11 in the United States. That means Hawaii, southern California, and the southern tips of Texas and Florida. If that’s you, here are some tips for growing one of these magnificent trees in your yard:

• Make sure you have enough space. Expect it to grow about 3 feet a year, reach 100 feet tall, and have a canopy 60-100 feet wide.
• Plant it where other trees or your house will shelter it from the wind.
• It does well in temperatures of 70-85 °F and high humidity.
• It needs full sun to make the bark as vibrantly colorful as possible.
• Give it deep, fertile, sandy loamy soil. Some growers say it is not picky about the acidity of its soil, but a pH level of 5.6-6.0 is ideal.
• Water it regularly during the first year, but don’t overdo it. They need well-drained soil and do not tolerate being waterlogged.
• It doesn’t need fertilizer unless the soil is extraordinarily poor.
• You can prune damaged or diseased branches in late winter or early spring. Other than that, no pruning is necessary unless you want to do it for aesthetic reasons to maintain a particular size or shape.

Growing a Rainbow Eucalyptus Indoors

If you’re container-growing this species in a cooler climate, growing instructions are much the same:

• Keep it in full sun. Use a grow light to supplement the natural sunlight in winter.
• Keep it well-watered and well-drained.
• Plant it in a pot about 2 feet in diameter to give it room for root growth.
• Keep it indoors in cool weather, but you can take it outside when the temperature is in the 70s and above. It cannot tolerate dips in temperatures below 50 °F.

Propagating Rainbow Eucalyptus

This species can be propagated from cuttings only until the plant is about 5 years old. After that, the cuttings will rot because of a chemical in the plant. To propagate from seeds, starting indoors, get a large container and surface sow the seeds. Cover, place it in a sunny location, keep the soil moist and the temperature at about 90 °F. Germination takes 1-3 weeks and the seedlings are ready to be planted outside at 12-15 months old.

Where Can You Buy Rainbow Eucalyptus Trees or Seeds?

If you live in parts of the country where these trees can be grown outdoors, you’re likely to find them at one of your local nurseries. Otherwise, you’ll find plenty of nurseries online selling saplings and seeds at affordable prices. A 30-48″ tree sells for $50-$100 and you can find packs of 100 seeds for as little as $5. It’s a small investment to make in preserving a vulnerable species and bringing the most artistic tree in the rainforest right into your own home.