Delivery is free. Learn more about the pests and diseases threatening our trees. Find out how to spot them, the symptoms and outlook, and how you can help. Eucalyptus Eucalyptus spp. What it looks like Where to find it Value to wildlife Uses and mythology Threats. Quick facts. Common name: eucalyptus, gum tree Scientific name: Eucalyptus sp. Family: Myrtaceae Origin: non-native. What does eucalyptus look like? Not to be confused with: Two of the most common species of eucalyptus in the UK — the cider gum Eucalyptus gunnii which can be found in great numbers on the Essex coast, and the Tasmanian blue gum Eucalyptus globulus which is the main source of eucalyptus oil and grows plentifully in Cornwall and Ireland.
Trees woods and wildlife. Download the app. Where to find eucalyptus These aromatic trees are native to Australia and only about 12 of the many species grow in the warmer regions of Europe. Value to wildlife.
Mythology and symbolism Australian indigenous populations used eucalyptus for spiritual cleansing. Over time, as this layer is exposed to air, it ages into different colors—bright reds, oranges, blues, pinks and purples. The different colors appear as different layers fall off, while other exposed areas begin aging. This process creates a spectacular visual, resembling a multi-colored crayon scratch drawing, covered with black crayon that is then scraped away to reveal the multi-colors underneath.
Rainbow eucalyptus is the only eucalyptus tree indigenous to the northern hemisphere. Eucalypts are evergreens. Unlike many northern hemisphere trees that are deciduous in harsh times such as winter, eucalypts have leaves all year. The leaves are thick, leathery and tough due to lignin, and do not easily wilt. This enables them to survive hot and dry conditions. Eucalypts also develop very different leaves as they grow from young juvenile plants to adult trees.
Often the juvenile leaves are held horizontally to maximise light absorption but as adults the stalk of the leaf twists and the leaves hang vertically to reduce exposure to high levels of radiation and water loss.
The internal anatomy of the leaves also changes. A unique feature of the eucalypts is the caps—called opercula—that cover the flowers when in bud. These caps are the equivalent of the showy petals and sepals of other flowering plant.
The opercula prevent the flower from drying out and along with oil glands in the tissues, help protect it from insect attack. Plants limit their use of water by creating thin layers of humid air around their leaves through transpiration.
Wind rapidly whisks away this humid air and replaces it with dry air. As a result, the plants must use more water to thrive in a windy environment. When farmers reduce wind with windbreaks, plants can keep that layer of humid air around their leaves, and therefore use less water to grow. In drought-prone places, such as California and Australia, windbreaks are useful in reducing the amount of water crops use. They can also improve crop yields. The eucalyptus genus, as mentioned above, is large and very diverse.
To make sense of the genus, some botanists break it down into two broad categories of eucalypts; mallees and trees. These categories correspond to different growth habits within the genus. These categories provide a useful framework to understand the growing habits of eucalyptus.
Mallee is an Australian Aboriginal word that refers to bush eucalyptus species that grow less than 30 feet tall. Mallee eucalyptus have many different stems, rather than one central stem. Mallee eucalypts have lignotubers, which are huge, basically like big, potato-like roots.
These lignotubers suck up water during wet periods and save it for droughts. In Australia, mallee ecosystems grow best in flat, semiarid environments with short, mild winters. They typically grow in sandy soils and are adapted to frequent fires. The lignotubers allow the mallees to sprout back quickly after a fire, allowing for new growth.
Since mallee forests are in flat areas and have a relatively uniform height, they can be disorienting, causing people to get lost! Some of the more common species, such as the southern blue gum, lack branches on the bottom half of their trunks, while others have branches all the way up.
There are over species of eucalyptus — not to mention subspecies — in the world. With a dizzying array of eucalyptus available in the horticulture world, it can be tough for the layperson to identify the trees.
Here are a handful of the most commonly grown gum trees in the U. Southern Blue Gum — Eucalyptus globulus. Fun Features: Southern blue gum is among the tallest tree species in the world. It can soar into the sky nearly feet in Tasmania! This Tasmania blue gum tree is the most common eucalyptus in California and around the world because of its extreme drought tolerance, fast growth, and stately form.
Up to nearly feet in nature, feet in cultivation. Widely adaptable, but can tolerate very dry conditions as well as saturated river banks.
Grows well in clay soils, slightly acidic soils, and nutrient-poor soils. Prefers full sun, can grow in part shade, but not full shade. Native to higher elevations in Australia, Cider gum is considered one of the most cold-hardy , single trunk eucalyptus trees.
This is one of the reasons it is the most commonly grown eucalyptus in the cold British Isles. Widely adaptable to soils; it can tolerate nutrient-poor areas. Snow gum grows in an interesting, gnarled manner.
The twists and turns in its bark can make for a stunning small tree. Snow gun, as its name insists, does better in colder climates than most species of Eucalyptus. However, it can withstand some drought. Close-up of attractive silver dollar gum leaves. Silver dollar gum has rounded leaves that give off a grey, silvery-white shine on the underside.
From certain angles, they look like cent pieces! Silver dollar gums are the second most common Eucalyptus in California.
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