Eucalyptus Plant Identification: Types (Rainbow, Blue, Gum) How To Grow

Most people know that the Eucalyptus plant produces excellent remedies for clearing head congestion, thanks to it’s minty properties.

But, did you know that the famous “rainbow tree” is also a Eucalyptus? It’s true.

With brightly colored bark, the tree is famous for it’s startling design.

But, even if you don’t live in a tropical area, you can enjoy growing Eucalyptus plants.

This complete guide explains the various types of eucalyptus plant varieties, as well as how to grow them indoors and out.

Rainbow Eucalyptus Tree

Although it might look plain, beneath its thin, gnarly exterior, the bark of the tree features bright reds, greens, and purple colors streaked along the trunk in haphazard patches, colors that exist on no other tree on earth.

This Rainbow tree is native to the Philippines, while most other species flourish in the Southern Hemisphere, but other types of Eucalyptus Trees are now grown worldwide.

They are famous for being fast-growing trees, for providing essential oils, and for the relaxing sensation imbued with every inhalation of the fragrance wafting from the leaves.

They are sufficiently adaptable to be grown indoors in containers, as small decorative shrubs in gardens, or as towering giants in backyards big enough to accommodate them.

And there are a lot to choose from.

Related Reading: What Country Has the Most Trees? View World Forest Map (New Forestry Areas)

Eucalyptus Plant Growing Zone (Growing Types, Locations, Indoor & Out)

Comprising more than 700 species it is no wonder that the Eucalyptus Tree has migrated far and wide from its native shores of Australia, its menthol-flavored leaves coveted for medicinal and therapeutic purposes.

In fact, Researchers have recently discovered that the oldest known Eucalyptus fossils have been found in South America.

In the United States they grow best in USDA hardiness zones 8-11 where the medium temperatures hover around 65°F to 75°F and the humidity levels are moderate.

(Image: Max Li¹¹)

The trees can tolerate times of drought so planting in a slightly acidic soil that is well-draining is important for continued plant health. Extended dry periods are not good for the trees and this will reflect in the leaves drooping.

A quick test to ascertain if your tree needs a splash of water is to insert your finger into the soil at the base. If it is bone dry then regular weekly watering may be required if the area is going through a dry spell.

Containerized Eucalyptus plants that are located indoors need to be monitored more often than the ones outdoors, despite their hardy reputation.¹ Watering them can easily be forgotten and a disadvantage that they have is that they will not benefit from the natural rainfall that plants outside enjoy.

Potted plants can have the best of both worlds, spending summer months in a Sunkist spot in the garden among the birds and bees, and then when the winter encroaches they can be brought back indoors. Even If there are wintry days where the temperature is relatively high, the plant can be placed outside and brought back indoors at night if the temperature drops below 50°F.

How To Identify Eucalyptus Plant (Eucalyptus Plant Flower and Eucalyptus Plant Seeds)

If you need to know which tree is the Eucalyptus plant, just ask a Koala bear (which is actually a marsupial). On average, they consume between 500g to 800g of these water-laden leaves on a daily basis, all within a 4-hour window.

After wolfing down leaf after leaf, they need to take a brief nap for 20 hours, worn out after leisurely munching away on their favorite snack. Absent these cute cuddles, there are other ways to tell the species of these trees – and it’s not by tasting one of the leaves to test the distinctive menthol flavoring.

To most animals and humans, ingesting the leaves will lead to a very negative reaction as they are known to be highly toxic. Yet, their shape and aroma are one of their most unmistakable identification signs of which tree this is.

The seeds are also unique to these trees, encased as they are within a pod that is small at one end and round and flat on the opposite with a wide base. The flowers on the Eucalyptus plant do not have petals, relying instead on the stamens to grow into fluffy balls of white, red, yellow, or pink to pretend to be flowers that are made more visible among the green leaves because of the contrast against the brown gum nuts.

(Image: Caroline Jone¹²)

Combine all these traits with the ever-peeling bark, and identifying a Eucalyptus plant is far easier than you may think.

Types of Eucalyptus Plants and Eucalyptus Plant Identification Guide

One of the names for the Eucalyptus cinerea tree in its hometown of Australia is the medicinal tree,² and deservedly so.

The oil from the leaves has been used to relieve congestion, heal wounds, as an antiseptic treatment, reduce fevers, relieve joint pain, and also in numerous products to aid in relaxation.

Other types of Eucalyptus Trees have their strengths, weaknesses, and medicinal uses. Let’s see where the best hardiness zones are for these other Eucalyptus plants and which ones are either more suitable for growing in indoor containers or growing tall in the great outdoors.

Rainbow Trees in Hawaii (Hawaii Rainbow Eucalyptus Tree)

Hawaii is one of the most attractive destinations for a break from the realities of everyday life.

Tourists flock there every year for the pristine beaches, to marvel at the active volcanoes rumbling in the background, and to take thousands of pictures of the unusual multi-colored Rainbow Eucalyptus Trees that were first introduced to the island back in 1929.

(Image: Forest and Kim Starr¹⁴)

No two trees are alike, the thin bark peeling away from the trunks constantly during the year to leave streaking colors ranging from light green to dark purple. Even these exposed colors are constantly changing as they are exposed to the elements at different periods of the year and different durations.

Ascending to heights of up to 250 feet, they are incredibly photogenic, but the kaleidoscopic display doesn’t last forever. The coloration only endured until the bark is ready to be shrugged off in strips once again as nature rejuvenates the trunk with a new skin.

By the time that is complete, all the colors have once again faded to brown, and it looks just like any other tree in the forest. The one next to it, however, is still in the first phase of shedding its bark so is all primed for the next round of photos.

Eucalyptus Plant Indoor (Rainbow Tree)

Is it possible to grow your very own Rainbow Tree to impress the neighbors on the front lawn or even in an indoor setting for your private appreciation? Or is a tree that grows up to a height of 300 feet a bit too big to have as a houseplant?⁴

There are parts of the United States that have comparable climates to Australia such as Texas, California, Florida, and, of course, Hawaii, where these trees will thrive.

If you are lucky enough to live in any of these zones, then growing a Rainbow Eucalyptus Tree is definitely possible.

Related Reading: How Many Trees Are in the United States? 6 Shocking Stats

And the good news is that the heights generally don’t exceed 100 feet, which can be reduced further by regular pruning. States in USDA hardiness zones 4-8 can also accommodate them as daytime temperatures are hot enough to provide the full 5-6 hours of daily direct sunshine required.

Nighttime temperatures can drop quite low and be too chilly in the fall and winter, however, so it is always advisable to bring them into an indoor setting at the first sign of frost. To do that, growing in a container makes more sense.

The best-growing conditions for Eucalyptus plant are where they can bathe in full direct sunlight with temperatures of 65°F to 75°F. However, they can withstand periods of discomfort in cold and dry environments as long as it is only temporary.

Growing Eucalyptus Plant From a Seed (Growing Eucalyptus Plant From a Seedling)

For many different types of trees, it is possible to propagate using various methods. Many new gardeners wonder-if it is better to start growing Eucalyptus plant from a cutting, from a seedling, or from seeds.

The problems encountered when trying to grow from cuttings are that some species find it difficult to root properly and it’s a coin toss whether it will be successful or not. Seedlings are a better option over cuttings, but they can have difficulties acclimatizing to the local soils which can be markedly different from the one in which they grew up.

By far the best method to be in control of the quality of the plant from the start is by growing from seeds. To get the rainbow project off the ground, the first step starts with the size of the container.

At a minimum, it needs to have a diameter of 2 feet with more than enough drainage holes so wet feet syndrome does not become a problem. Some seeds from certain types of Eucalyptus Trees need to go through the stratification process before they can be introduced to the soil in the container.

This cold treatment method artificially interrupts the seeds’ dormancy period so that germination occurs quicker.⁵ The process involves placing the seeds in a zip-lock bag filled with perlite and vermiculite and leaving them in a refrigerator with a temperature of 33°F to 40°F until the shoots begin to appear.

This normally takes between 4-6 weeks but can vary depending on the species.

How To Grow Eucalyptus

Once the seeds are ready for sowing it’s best not to disturb the roots unduly by shaking them free from the soil they have been in for the last month or so.

Fill a container, one that is not made of heavy clay, with a seed-starting mix such as peat moss or perlite with a layer of pebbles spread on the bottom to help with draining.

(Image: Lingeshtt¹⁵)

Using regular garden soil is not advisable as the sudden immersion into foreign soil may be a shock to the fledgling root system. When the pot is fully prepared, follow these steps.

• Sow the seeds with the sprout pointing down and gently cover them with soil
• Place in indirect sunlight where the temperature is warm but not overly hot
• Spray with water just enough to moisten the soil
• Transplant into a larger pot as the roots grow. Ensure that the top of the root is at the same level as the soil, and add a slow-release fertilizer
• It’s always prudent to change into a much larger pot than needed as Eucalyptus Trees are known as fast growers
• If in zones 9-11, the container can be situated outside as long as it is protected from heavy winds and gets more sunlight
• Ensure that the root ball, still encased in the soil from the container, is just slightly above ground level before backfilling with native soil
• Water thoroughly
• Apply mulch around the seedling to control water saturation, taking care to leave a gap between the base to avoid problems

Eucalyptus Trees do not require constant care and attention to be grown successfully, whether indoors or outside.

For the first couple of years, they require the application of liquid fertilizers if they have been pruned aggressively to control their growth and until they become firmly established in the soil.⁶ Occasional mulching can help.

Re-potting every two years for indoor plants is recommended to prevent the roots from becoming congested, and always use plastic pots as they are lighter to move from A to B.

Follow these steps, and a pot-sized Rainbow Tree can be in a sunlit corner of your home in no time, or a taller version can be grown in your front garden as a prized possession in a prime position.

Eucalyptus Plant Disease Prevention (How To Stop Eucalyptus Plant Disease)

There is a disease called Eucalyptus rot that infects the Eucalyptus plant through its leaves, flowers, and fruits. It presents as pustules that turn the leaves yellow after a few days, and in worst-case scenarios, defoliation can occur.

The spores from this infection are very transmittable not only from plant to plant but can also travel across boundaries between states, and even countries. If not tackled early an outbreak can create an emergency situation where the disease can spread to other plants in the area.

(Image: Chiara Coetzee¹⁶)

The recommended treatment if this is detected in home gardens is to spray with a fungicide specifically for this infection.⁷ If that is ineffective, or the infection keeps recurring, the remaining option will be the removal of the plant itself.

Before uprooting or moving the plant if it is in a container, liberally spray it with a fungicide or with water to prevent the spores from spreading. Nearby plants can also be sprayed for protection.

Potted plants should be plastic-wrapped before disposal and care should be taken when uprooting any trees or shrubs so that cross-contamination does not occur.

Two other serious fungal infections that can spell the demise of the Eucalyptus plant are.

• Cankers

This fungal disease attacks the outer bark before seeping inside the tree itself. The damage is noticeable from yellowing leaves to branches falling off and even girdling the trunk.

Can be fatal.

• Heat or trunk rot

This infection is hard to detect quickly as it actually occurs within the tree, attacking it from the inside out. By the time the fungus is detected, the tree is generally too far gone to be saved.

Preventative measures are the only way to protect Eucalyptus plants from invasive diseases such as these.

Periodically spraying with a fungicide called bacillus subtilis or multipurpose fungicides will stop them before they can set up home out of sight behind the bark and ruin the colors on your gorgeous Rainbow Tree.

Planting Tips for Eucalyptus Plant (Companion Plants for Growing Eucalyptus Plant)

Certain Eucalyptus plants are more suited than others for growing in containers in an indoor environment. Eucalyptus gunnii (cider gum), Eucalyptus cinerea (silver dollar), and Eucalyptus archeri (alpine cider gum) are three such varieties.

When planting in outdoor landscapes, there are more options available that can be equally successful if a few rules and tips are followed, whether growing as a shrub or a fully grown tree. A sunny spot and well-draining soil are crucial.

(Image: Max Li¹⁷)

As the plant grows, which it does very quickly, it needs to be pruned frequently to shape it and maintain its overall health. Companion plants such as those listed below will also help to ward off pests, and diseases, and just enhance the appearance of the Eucalyptus plant in your garden.

• Basil

Planting these close to Eucalyptus plants improves the flavor of the Eucalyptus leaves and conversely the leaves of the basil plant.

• Rosemary, thyme, and mint

The mingled scents from these plants combine well with the Eucalyptus and they all ward off certain pests.⁸

• Daffodils, marigolds, salvia, lavender, and nasturtiums are fragrant and colorful flowers that will grow well in various hardiness zones around your tree and will add impressive splashes of orange, red, yellow, and purple.

Facts About Australian Gum Tree and Eucalyptus Stem

The Eucalyptus Tree is also known as the gum tree because of the gooey sap it excretes. This bi-product has been used to make adhesives and as a remedy for toothaches.

There are myriad uses for all parts of the tree that are worth discovering, first and foremost being the beneficial uses for the most famous – Eucalyptus oil.

• There are 3 categories for the uses of the oil distilled from the Eucalyptus leaves – medicinal, industrial, and aromatic
• The compound that is responsible for this specific oil content in the leaves is a colorless liquid called cineole
• An unusual benefit of this substance is that it controls the mosquito population and is often planted in high malaria infectious locations
• Native Australian aborigines nicknamed the tree the fever tree due to its ability to treat coughs, asthma, joint point, and fevers
• In Australia, any Eucalyptus species that grows below 30 feet is called a mallee
• Ingesting the leaves or drinking the oil is toxic to humans and animals alike so should be avoided. Some symptoms are drowsiness, headaches, vomiting, and even comas that could lead to death
• Placing a few cut stems in a vase will create a natural air freshener
• The stems are also excellent insect repellants and have hypoallergenic properties
• The leaves can be dried and steeped in water to make herbal teas
• Because they are so fast-growing, Eucalyptus Trees are very beneficial in the fight against climate change and the reduction of greenhouse gas emissions
• But what the Eucalyptus Tree is surely more famous for is that its timber is the best for making the iconic didgeridoo!⁹

The Baby Blue Eucalyptus: Spiral Eucalyptus (The Eucalyptus Plant)

The Eucalyptus plant can be characterized by its diversity, hardiness, and ability to adapt to new environments.

With a range of species such as the Baby Blue that grows to heights of 40 feet with round, fragrant blue-green, and sometimes silvery leaves, to the ultra 300-foot tall and colorful Rainbow Tree, to the small but no less impressive spiral Eucalyptus shrub, there is something for every garden.

The small round leaves of this plant cling to the stem in such a way that they appear to be growing in a corkscrew manner which is very unusual. They make excellent decorative houseplants, and when cut can last up to 25 days in a vase.

If you plan growing Eucalyptus plant and trees to diversify your garden, make sure that you understand the dangers to nearby animal life and take precautions.

Frequently Asked Questions About Eucalyptus Plant