Eucalyptus subcrenulata

Eucalyptus subcrenulata, also known as Alpine Yellow Gum, is a botanical species native to the highlands of Tasmania, the southern island of Australia. Because of its distant mountainous origin from the Tropic of Capricorn, it displays good hardiness, which makes it easier to acclimatise in our gardens. A tree with moderate growth, it reaches about fifteen metres in height with a conical to slightly spreading habit. Although its flowers are of little interest, it is decorative due to its beautiful smooth bark where different shades mix, as well as its lovely bright green, evergreen foliage. Tolerating a little limestone in the soil, it grows in the sun in humus-bearing, well-draining soils, not too dry in summer.

Eucalyptus subcrenulata belongs to the large Myrtaceae family, like the Callistemon (Bottlebrush), the Feijoa or the Myrtle. The Eucalyptus genus has more than 800 species, virtually all native to Australia, except for a few from Southeast Asia. This one is endemic to Tasmania, an island in the extreme south of Australia, it develops there in the central part, in highlands and alpine regions. This Eucalyptus most often grows on slopes that are humus-bearing and rocky, well exposed to the sun.
With moderately fast growth, it forms a medium-sized tree, 15 to 20 m (49 ft 2 in to 65 ft 7 in) high, and half as wide. The trunk is generally clear at the base, and supports conical branching, with a sometimes slightly spreading crown. The very smooth bark displays a beautiful combination of colours, pale grey, beige or brown, and green-yellow. Like most species, this Eucalyptus has a juvenile foliage different from the adult. The young leaves are sessile (without petiole) and opposite, ovate in shape. Then, the adult foliage has an alternate arrangement, with lanceolate leaves, measuring 5 to 13 cm (2 to 5.1 in) long and 2 to 4.5 cm (0.8 to 1.8 in) wide and equipped with petioles up to 3.5 cm (1.4 in) long. Containing glands rich in essential oils, they give off a spicy scent when crushed. They are evergreen and lovely, shiny green.
Flowering occurs mainly between December and March in Tasmania (in the southern hemisphere which corresponds to our summer). The insignificant inflorescences gather in 3 floral buds, which open onto small white flowers of which we mainly see the 2 cm (0.8 in) diameter stamen. They then evolve into small fruits, greenish to brown-grey, also insignificant.
This Eucalyptus has several interesting features for ornamental use. Firstly, its hardiness of around -15°C, which allows it to be planted in most regions. Then, although it prefers neutral to acid soils, it tolerates limestone soils quite well. Finally, while it does not like drought, it is still quite tolerant of most conditions, just not tolerating excess water (it needs draining soil).

Eucalyptus subcrenulata will allow many garden owners to enjoy a species that is relatively easy to acclimatise, and much less known than the classic E. gunnii. This medium-sized tree can be planted alone or in the background to give an exotic air to the garden, even in a cool climate. It can then be associated with bushes like the Grevillea juniperina, very decorative with its dark green foliage that highlights its long-lasting bright red flowering. In a milder climate, the Azara microphylla, or Chilean Mimosa, will also be a good companion with its small dark green leaves enhanced by its delicately scented yellow spring flowering. To complete the scene, a few feet of Phormium in various colours, green, purple, variegated with yellow or other, will look great at the foot of this Eucalyptus.