Aromatic Eucalyptus from Seeds

In short: Sow eucalyptus seeds on the surface of a light, well-draining substrate and do not cover them – they need light to germinate. Keep the container covered at 18–22 °C; seedlings usually appear within 2 to 3 weeks. In our climate grow eucalyptus indoors and move it outside only for the summer.

Eucalyptus, also known as gum tree (lat. Eucalyptus globulus), belongs to the myrtle family (lat. Myrtaceae). The native home of these trees is Australia, Malaysia, Indonesia, and New Guinea. However, it has successfully acclimatized and is commonly cultivated in many countries. During the Cretaceous period and the Tertiary era, it also grew in our territory. This is evidenced by leaf and fruit impressions in sediments from that time. Today, mature trees can only be seen in botanical gardens here. The eucalyptus genus comprises more than 700 species. All representatives are characterized by very rapid growth, which can reach several meters per year in the wild. The tallest specimens can grow to a height of up to 100 meters. The group of tallest eucalyptus species includes Eucalyptus obliqua, Eucalyptus delegatensis, Eucalyptus diversicolor, Eucalyptus nitens, Eucalyptus globulus, and Eucalyptus viminalis. Several eucalyptus species are even among the tallest trees in the world. Their rapid growth and consequently large water consumption is used in their homeland to drain swamps and marshes, thereby preventing mosquito breeding and subsequent malaria transmission. This characteristic of eucalyptus is especially welcomed during floods.

Eucalyptus trees are mostly massive trees with smooth trunks whose bark occasionally peels off. The appearance of the bark changes with the age of the plant. The length of bark fibers, degree of wrinkling, thickness, hardness, and color gradually change. All mature eucalyptus trees add a new layer of bark annually. The bark surface can be matte, glossy, or satin, in colors of white, cream, grey, green, or copper. The leaves of eucalyptus are also noteworthy, as they are dimorphic. Light green, sessile, opposite leaves grow on young shoots, whereas leaves on older shoots are alternate, stalked, sickle-shaped, up to 30 cm long. Their blades are vertically inclined to capture as few sun rays as possible. Eucalyptus groves, referred to in Australia as mallee scrub (scrub = shrubland), are therefore very bright with little shade. This is how the plant protects itself against excessive water evaporation. Flowers grow in leaf axils; the calyx and corolla petals fuse into a cap that falls off when blooming, leaving only the stamens on the plant, of which there are a considerable number. It was precisely the flower that inspired the Greek name from which eucalyptus is derived. The name is composed of the words "eu" and "kalyptos", translating as well covered. In this case, it is the flower stamens that are well covered. The fruits are woody capsules of conical shape. Each contains many seeds.

Eucalyptus is one of three similar genera commonly classified as eucalypts. The other two are Corymbia and Angophora. Many eucalypts are referred to as gum trees because a large amount of sap flows from wounds when the bark is damaged. Eucalyptus is also known by the synonyms aromadendron, eucalypton, eudesmia and symphyomyrtus.

Three species of eucalyptus are most commonly grown indoors, which don't reach excessively large dimensions (with regular pinching). These species are Eucalyptus gunnii, Eucalyptus citriodora and Eucalyptus globulus.

Eucalyptus globulus is also known as Tasmanian blue gum. This eucalyptus species is among the most well-known. Its easy-to-grow cultivars are cultivated for their aromatic essential oils. The leaves are larger, round, waxy and emit the typical eucalyptus scent. Eucalyptus gunnii originates from Tasmania. It is rather small to medium-sized, with narrower and oval leaves. Eucalyptus gunnii flowers in midsummer. This eucalyptus is relatively cold-hardy compared to others - it can withstand temperatures down to -13°C, and briefly even -20°C. Currently, it's grown mainly for decorative purposes and for scenting indoor air. Eucalyptus gunnii can also be grown in sandy areas with relatively moist soil. The last commonly cultivated species is Eucalyptus citriodora, alternatively known as lemon-scented gum or lemon eucalyptus. This species contains large amounts of eucalyptus essential oils (citral and citronellol) which are released even by the slightest touch or breeze. An intense lemon scent then wafts around the plant. Lemon eucalyptus is particularly suitable for apartments, where mature plants create a microclimate that helps humidify the air and has antiseptic properties. Lemon eucalyptus helps asthmatics improve their health condition. Seeds germinate easily and otherwise plant care isn't particularly complicated. In optimal conditions, the tree could grow up to approximately 50 metres in height, which is highly unlikely to happen if you regularly pinch out young shoots. A major advantage of this eucalyptus is that its lemon scent effectively repels insects.

Tip: Eucalyptus oil is suitable for inhalation, bathing or massage.

Growing Eucalyptus

In our conditions, eucalyptus is grown exclusively indoors. Although some species are frost-resistant, they would most likely not survive a long-lasting winter. However, during the summer period, the plant can be moved outdoors without any problems. In winter, when there is a lack of light, it is more suitable to place the plant in a cool room to prevent it from stretching too much. Growth dormancy occurs, which leads to lower water consumption, so water the plant very carefully in winter, preferably only when the top leaves show slight wilting. During the summer period, plants prefer a bright location. In such a place, however, you must expect higher water consumption. Do not expose young plants to direct sunlight as it could damage them. Plants need to be regularly pinched back, which prevents excessive growth and encourages more branching. When repotting eucalyptus, you must not damage the roots, as the plant is very sensitive to this. Due to the high content of essential oils, eucalyptus is usually not attacked by pests - rather, it repels them. The substrate for cultivation should be permeable, loamy-sandy, which can be prepared by mixing ordinary soil, sand and peat. New plants can be obtained using seeds or cuttings, although the latter is very difficult. Sow seeds preferably from spring to autumn at a distance of approximately 5 cm. Young seedlings will germinate from the seeds after approximately one week to one month, depending on soil quality and temperature. The seeds are very small, so sow them on the surface of the substrate and press them down gently. After germination, water the substrate regularly, as seedlings require a warm and humid climate. The best germination rate is achieved at temperatures above 20 °C. Repot young seedlings only when they reach a size of approximately 15 cm. In subsequent years, repot young plants every spring; older ones only need repotting once every 2-3 years. When moving the plant between summer and winter locations, it often happens that despite following cultivation procedures, the plant starts to dry out and shed leaves. However, this is usually not a problem. In spring, prune the dried branches and new ones will soon begin to sprout. By the end of June, thanks to its rapid growth, the plant should have a representative appearance again.

Uses of Eucalyptus

Eucalyptus has positive effects thanks to its essential oil content, especially on the respiratory system. In the form of herbal preparations, it is used to treat bronchitis, sinusitis, coughs and colds. It benefits asthmatics. It also contains a large amount of cineole, which is used in medicine and cosmetics as a disinfectant. Eucalyptus is added to ointments for rheumatic pain, or its leaves can be soaked in alcohol for 2-3 months and the resulting liquid is then applied to rheumatic areas. Shortly after application, muscle and rheumatic pain is relieved. Eucalyptus has antiseptic effects, improves blood circulation in the skin, helps against headaches and supports healing processes. Eucalyptus oil is also used in the production of perfumes and various essential oils. To fragrance your home and for invigoration, you can buy tea candles with eucalyptus scent. Wardrobes can get a pleasant aroma by placing dried excess shoots inside. Inhalation of eucalyptus oil vapors also has a beneficial effect on the psyche, it can help suppress anxiety attacks, panic fear and has antidepressant effects. It releases not only psychological blocks, but also eliminates physical exhaustion. Eucalyptus oil is also excellent for massaging a blocked cervical spine. It induces pleasant feelings. Eucalyptus cream helps relax tired calves. Veterinarians use eucalyptus oil as a medicine for horses when they get flu, and prescribe it to dogs as a disinfectant against distemper.

Eucalyptus oil must not be taken internally (you're not koalas), as it can cause poisoning, which manifests itself through vomiting, dizziness, stomach pain, muscle pain and constricted pupils. No adverse effects of eucalyptus have been proven with external use, but it should not be used during pregnancy and breastfeeding.

What You May Not Have Known About Eucalyptus...

• Its leaves are a very popular delicacy for koalas and possums.
• In Australia, eucalyptus trees make up to 95% of local forests.
• Its wood is not of very high quality; it is used for paper production.
• In its homeland, it is important for honey production.
• They are always evergreen trees.
• Eucalyptus trees in Australia have such strong bark that they can even withstand fire.
• Eucalyptus pauciflora can survive frost down to -20°C.
• Eucalyptus wood is used to make didgeridoos, which is a traditional Australian wind instrument.
• Eucalyptus can be used to produce dyes, mainly for silk and wool.