Eucalyptus obliqua

Eucalyptus obliqua is among the giants of the genus, capable of reaching nearly 90 m (295 ft 4 in) in height in its native regions. Forming a tree with a relatively narrow and very erect habit, this imposing tree is adorned with a thick and rough, brown or greying bark. Its evergreen foliage of a beautiful shiny green is decorative all year round. In spring, small white pompom-like flowers appear, but this flowering remains quite discreet given the dimensions of the tree. Resistant to wind, it requires a neutral to acidic, well-drained soil, and grows well in a humid climate. Its low hardiness limits the possibilities of acclimatising it.

Eucalyptus obliqua belongs to the large family of Myrtaceae, like the Callistemon (Bottlebrush), the Feijoa or of course the Myrtle. The Eucalyptus genus includes more than 800 species, almost all native to Australia, except for a few from Southeast Asia. Some form small bushes, while E. regnans is the giant of the genus, closely followed by E. obliqua.
This species originates from a wide area extending from southern to eastern Australia (States of South Australia, Victoria, New South Wales, to southern Queensland), as well as almost all of Tasmania. It grows just as well in coastal areas, on hillsides or in cool mountainous situations, up to 1200 m (3937 ft) in altitude. It develops on various types of soil, always well-drained, in humid forests, along with other large Eucalyptus species, such as E. nitens. Over such a vast geographical area, this tree is confronted with different climates, including warm summer temperatures, light but frequent frosts in winter, and annual rainfall from 500 mm (19.7 in) to over 2 m (6 ft 7 in).
This monumental tree, the largest living specimen currently measures 86 m (282 ft 2 in) in height (in the past, subjects approaching 100 m (328 ft 1 in) in height have been identified...) forms an endless trunk whose diameter can reach 3 m (9 ft 10 in). It also has the quite common characteristic among Eucalyptus, of developing a lignotuber, an underground formation rich in starch intended to rebuild the above-ground part in case of destruction (especially by fire). It thus has the ability to regrow from the stump, with many axillary buds developing in all directions.
Growing in a forest, this tree generally has a rather erect habit due to the competition between individuals. Planted alone, its crown opens and takes on a more spreading aspect. The massive trunk is covered with thick and rough bark, fibrous or stringy in appearance (hence its English name of stringybark). This bark extends to the branches, although sometimes those of small diameter have smooth bark.
The juvenile foliage has more or less ovate leaves, with a slightly wider base and a refined tip, measuring from 6 to 21 cm (2.4 to 8.3 in) long and 2.3 to 8.5 cm (0.9 to 3.3 in) wide. The green leaves carried by short petioles are opposite. Adult leaves have roughly the same format, albeit slightly narrower, lanceolate to slightly crescent in shape. Green with a shiny surface, they are easily recognised by their asymmetrical base, one of the edges of the lamina descending lower than the other, which gave this species its scientific name (from the Latin obliquus). This foliage is appreciated by koalas who are fond of it.
Flowering can occur almost all year round in Australia and is spread between March and June in our climates. Small white flowers, formed by the stamens (the petals are absent) are grouped in umbels of 11 to 15, thus forming pompoms in the axil of the leaves. They then evolve into fruits, brown urn-shaped capsules, without ornamental interest.
This giant tree appreciates humid, moist climates, but also accepts hot summers, provided it does not suffer from long drought. It withstands some cold, down to about -5°C, which restricts the possibility of acclimatising it. 

Eucalyptus obliqua will mainly interest collectors in areas with high rainfall. It will form a monumental subject planted alone on a lawn or in the background of a group. It is estimated that it could then reach 45 m (147 ft 7 in) in height for 15 to 20 m (49 ft 2 in to 65 ft 7 in) in width, which requires having a large plot for it. You can plant tree ferns at its foot, also lovers of humidity, to create a beautiful exotic scene. To further enhance this effect, why not be tempted by Wollemia nobilis, a rare Australian conifer with superb branches reminiscent of this distant continent.