Eucalyptus nicholii

Eucalyptus nicholii is an Australian species that forms a beautiful, medium-sized tree. Its well-balanced habit, with a strong trunk supporting a dense canopy with a rounded top, is both architectural and very aesthetic. It has superb evergreen foliage that is very elongated and fine, with a grey-green colour that matches well with the brown bark and reddish branches. Its white pompon-like flowering in late winter is quite decorative. Grown in neutral to acidic soil, in sunny exposure, it can tolerate hot summers, wind, salt spray, and moderate frost. A highly ornamental tree for medium-sized gardens.

Eucalyptus belongs to the vast family of Myrtaceae, of which it is one of the most prolific genera with about 800 species. Some are shrubby and do not exceed a few metres in height, while giants like E. regnans reach heights of nearly 100 metres (328 feet)! E. nicholii is native to Australia, where it grows in New South Wales, north of Sydney, in a temperate climate with hot summers and cool winters. It is mainly found on granitic and porphyritic soils, neutral to acidic.
It forms a medium-sized tree, reaching a height of 15 metres (49 feet) and a width of about 10 metres. The trunk is quite large and has a grey-brown to cinnamon-brown, fibrous and fissured, ornamental bark which persists up to the branches, while the young branches are a beautiful reddish colour, highlighting the foliage. Like many other species, it forms a lignotuber, which is a starch-rich swelling at the base of the trunk partly underground, allowing buds to sprout after a fire (or more generally, after the destruction of the aboveground part). 
The foliage has very little difference between the juvenile and adult forms, both of which are beautiful grey-green to blue-green. The juvenile leaves are linear to lanceolate, small in size (up to 6 cm (2.4 in) long and 1 cm (0.4 in) wide), sessile or with a short petiole and arranged in an opposite manner. The adult leaves have the same appearance but can be twice as long, carried by a short petiole and with an alternate arrangement. Equipped with glands containing essential oils, they emit a menthol scent when crushed.
Eucalyptus nicholii also produces beautiful white flowers in late winter. These are petal-less, round flowers composed of a multitude of tightly packed white stamens, resembling pompons. They bloom between the leaves, grouped in umbels of 7 along the branches, and are followed by the formation of small fruits, without ornamental interest. This flowering is unique in the plant kingdom, but typical of Myrtaceae, where stamens are often admired (as in the famous Callistemon, or Bottlebrush), and contrasts well with the red of the young branches.
Preferring hot climates in summer, this Eucalyptus can tolerate frost down to -8°C (17.6 °F), or even -10°C (14 °F) once well established. It grows in sunny exposure, in neutral to acidic, moist to moderately dry soils. 

This beautiful Eucalyptus deserves to be planted as a focal point to admire its very architectural habit, as well as in the background of a border to provide structure. Its beautiful coppery bark and fine foliage are assets for creating an ornamental scene. Have fun creating a strong architectural effect by planting a large-leaved plant next to it, such as the Japanese Medlar (Eriobotrya japonica), a large evergreen shrub that will reward you with its succulent orange fruits in mild climates. The Handkerchief Tree (Davidia involucrata) with its green leaves and large white bracts will also create a stunning contrast alongside the Eucalyptus. To create a colourful shrub layer, consider the Loropetalum, a shrub with green or purple foliage depending on the variety, which produces a splendid flowering with long ribbon-like petals in pink, red, or white, with an exotic look that will blend perfectly into your border.