Eucalyptus (Eucalyptus sp.) is an Australian tree species belonging to the Myrtaceae family. The species is wide-ranging, containing over 900 different variants, ranging from short, bushy plants to giant trees. Despite their differences, they are easily identified by their pungent aroma and exfoliating bark.1
Botanist David Nelson discovered the plant in 1777. He took a sample and brought it back to London, where it was given the name Eucalyptus obliqua by Charles-Louis L'Héritier, a French botanist, in reference to the plant's flower bud and the shape of the leaf, respectively. "Eu" means "well," while "calyptos" means "covered." "Obliqua," on the other hand, comes from "obliquus," which means oblique in Latin.2
In the following years, many other species of eucalyptus were discovered as more settlers and explorers began to explore the Australian landscape. James Edward Smith, another English botanist, discovered more species of eucalyptus between 1790 and 1802.3
You might be interested to know that the koala, an herbivore mammal native to Australia, is the only mammal that can survive on a diet consisting of eucalyptus alone. In fact, this plant species is their favorite food. Other animals can't digest or metabolize eucalyptus leaves, and it can even be poisonous to them.
The koala has the advantage of having a specialized caecum, which is a section in the digestive tract containing millions of beneficial bacteria that can break down the eucalyptus leaves safely.4
The rainbow eucalyptus tree (Eucalyptus deglupta) is a standout in the eucalyptus family. It can grow up to 250 feet tall, and as the name implies, has a rainbow-colored bark. This occurs when the tree sheds its bark during the summer, creating pale green, red, orange, gray and purple-brown bark streaks.5
Rainbow eucalyptus is mainly used for decorative and shade purposes, but it has various practical uses as well. It is prized for its wood and bark, which is used to make paper.6 If you're wondering if it's possible to grow rainbow eucalyptus in your yard, you can — as long as you live in a frost-free area with an area that has access to full sun and plenty of moisture.
However, you may want to think twice about planting a eucalyptus tree, as a mature rainbow tree can grow to be very tall and can quickly become a problem in your garden and your neighborhood, disrupting the soil and breaking up sidewalks. This tree is better suited to parks and fields that can be enjoyed by the public.7
The Australian aboriginal populations were the first to discover the health benefits of eucalyptus. Since then, more ways to use it medicinally have been discovered. Well-known benefits include helping:
• Eliminate bacteria — Eucalyptus was discovered to have antibacterial properties from early on. Toward the end of the 19th century, it was used in to disinfect urinary catheters, and recent research can support this claim.8
In a study published in the Asian Pacific Journal of Tropical Biomedicine (APJTB), researchers discovered that essential oil extracted from Eucalyptus globulus leaves is particularly effective against common strains of bacteria, such as E. coli and Staphylococcus aureus.9
• Promote oral care — The compounds found in eucalyptus may help promote oral health. In one study, participants who regularly chewed on gum containing eucalyptus extract had lowered levels of plaque accumulation, and had healthier gums overall.10
• Provide respiratory relief — Eucalyptus may help provide relief from runny noses, coughs and colds to help you breathe easier, as well as loosening phlegm,11 which is why you'll find it as an ingredient in many products, such as cough syrups, rubs and vapor baths.12
• Relieve pain — In one study, researchers applied eucalyptus ointment on participants and discovered that it was able to help provide temporary pain relief, making it useful for athletes after a game. Furthermore, findings suggest that it can be used as a passive form of warmup due to its ability to raise muscle temperature.13
Aside from using eucalyptus for its healing benefits, the Australian indigenous populations found other practical uses for it. According to Woodland Trust, the wood was used to make tools, weapons, canoes and musical instruments to fit their needs. Today, eucalyptus is mainly used to manufacture paper and furniture. Its leaves are also used to create essential oils for aromatherapy.14
When planted in your garden, eucalyptus offers several advantages. The strong aroma of its oils can help act as a natural insect repellant, while the wood can serve as mulch to help improve soil conditions in place of other popular potting mixes, such as pine bark.15 To make the mulch, simply distribute chopped eucalyptus wood or bark on the soil. The oils in the mulch can help repel plant-eating pests as well.16
Growing eucalyptus requires careful consideration. As mentioned, you need to ask yourself: Do you have a backyard that can accommodate a eucalyptus tree once it has fully grown? If not, you may want to choose a species that can fit into containers, so that it can be grown on your patio or another location in your garden. The guide below focuses on how to cultivate smaller types of eucalyptus.
• Preparing to Plant Eucalyptus — Most species of eucalyptus require full sun to reach their maximum capacity, but certain species can tolerate partial shade, such as E. neglecta and E. crenulata. According to Gardening Know How, another advantage of eucalyptus is that it can adapt to a wide range of soils, as long as the area has good drainage.17
Purchase seeds of your preferred eucalyptus species, sow them in a shady area in your soil during spring and then cover them in plastic. Once the seeds grow, transplant each seedling into small pots. You may sow seeds directly into containers as well.18
• Maintaining Eucalyptus — Once the seeds start to grow, little maintenance is needed. Watering should be done in moderation, and only done when the soil becomes dry. If your area is currently experiencing drought, you will have to increase the amount to compensate for the high temperatures. Fertilizers are not recommended when growing eucalyptus, as they can destroy the quality of the plants due to their phosphorus content.19
Pruning is important when maintaining your trees. You must control the top growth or else the plants will become too heavy and will become unstable. You will also need to clean the area around the trees for safety reasons, because the bark is considered flammable.20
• Harvesting and Storing Eucalyptus — You may cut the branches and leaves as the plant grows.21 Gathered leaves can be grouped into a bunch and air-dried upside down or wrapped in a paper towel. Once they're dry, store them in an airtight glass jar.22
One of the most common foods you can create from eucalyptus is tea. It allows you to enjoy all the nutrients in an efficient manner and is very easy to make. Just follow the steps below:23
- 1 dried eucalyptus leaf (or 1 teaspoon), crushed
- 6 ounces filtered water
- Raw honey (optional)
- Place the crushed eucalyptus leaf in an 8-ounce teacup.
- Bring water to a boil. Turn off heat and let it set for a minute to reduce the temperature slightly.
- Pour the water on the teacup and steep for 10 minutes.
- Strain the tea into a new teacup before drinking.
- Add a dash of raw honey if desired.
Note: Only drink eucalyptus in minute amounts. Drinking too much can lead to eucalyptus poisoning, which is marked by stomach pains, dizziness and muscle weakness.24 Do not drink eucalyptus if you have experienced an allergy reaction to the leaves or oils.
Eucalyptus essential oil is well-loved in the field of aromatherapy. There are around 500 different species of eucalyptus essential oil produced around the world, but "The Healing Art of Essential Oils" says these four are some of the most commonly used:25
- Eucalyptus globulus — This species is the top choice for creating eucalyptus essential oil, and is the ingredient used for various eucalyptus products as well.
- Eucalyptus polybractea — Also known as "blue mallee," it is high in cineole, which is a colorless liquid terpene with an odor similar to camphor.
- Eucalyptus radiata — Also known as "narrow-leaved peppermint," it is known for its refreshing aroma.
- Eucalyptus citriodora — Nicknamed the "lemon-scented gum," it is primarily used in perfume and industrial purposes.
The great thing about eucalyptus oil is that you can make it in your own home, especially if you have leftovers from making tea. Below are a few things you need to make infused eucalyptus oil:26
- Kitchen weighing scale
- 2 ounces eucalyptus leaves
- Olive oil or a different carrier oil
- Crock pot
- Small-gauge mesh strainer
- Airtight jar made of dark glass
- Gently crush the eucalyptus leaves with your fist to release the oil. You may use more or less depending on the size of your crock pot.
- Place the eucalyptus leaves in the crock pot.
- Add 1 cup of olive oil for every one-fourth ounce of leaves in the crock pot.
- Place the lid on the crock pot and turn it on at low heat. Let the mixture steep for six hours.
- Strain the eucalyptus oil through the mesh strainer and into the jar.
- Seal the jar and date it.
- Store the eucalyptus oil in a cool, dry spot, where it will remain viable for six months. If needed longer, store the oil in the vegetable crisper drawer in your refrigerator, where it will last for about a year.
Eucalyptus oil has diverse benefits when used in different ways. However, make sure you dilute this essential oil in a safe carrier oil before using. Areas it can benefit include:
- Skin care — Applying eucalyptus oil on your skin may help fight bacteria that can cause infection, including antibiotic-resistant strains.27
- Lice removal — Eucalyptus contains compounds that may help eliminate head lice.28
- Pain relief — Inhaling eucalyptus oil has been found to be helpful in managing pain and lowering blood pressure.29
Before using eucalyptus oil (or any essential oil), it's important to be aware of the side effects. Eucalyptus oil has been known to cause:30
- Burning sensation in the mouth and throat
- Abdominal pain
Always make sure that your doses are controlled. Aside suffering from the above symptoms, some victims of eucalyptus oil poisoning have fallen into a coma, while others have unfortunately died.31 Always check with your physician before using or consuming eucalyptus or any essential oil.