Eucalyptus perriniana

Eucalyptus perriniana is undoubtedly one of the most interesting species of its genus. Although fast-growing, it can still be planted in a small garden as its size always remains under 10 m (32 ft 10 in). Its coppery bark is decorative in all seasons, as is its evergreen foliage. The juvenile leaves have a beautiful bluish hue, and an original form, with the opposite and fused lamina being pierced by the stems. This Eucalyptus will bring exoticism to the gardens of many regions because in addition to being hardy down to -15°C (5 °F), it is one of the few to tolerate half-shade. Very adaptable, it grows in neutral to acidic soils and moderately tolerates limestone.

Eucalyptus is a tree of the Myrtaceae family, like the Feijoa, the Callistemon or the Myrtle, with flowering characteristics of this family. The Eucalyptus genus, from Australia, except for a few rare species from Southeast Asia, has more than 800 species, among which are the tallest leafy trees in the world (E. regnans), but also medium-sized bushes.
Eucalyptus perriniana originates from the south of Australia, from the alpine highlands of the state of Victoria to the southeast of New South Wales. It is also found at low altitudes, in southeastern Tasmania, the large island south of the mainland. It grows in different types of soil, from the rocks of Victoria to the sands of Tasmania, and under varied climates, mixing mild to hot summers and cold winters. This probably explains its good adaptability and hardiness, among the best in the Eucalyptus, as it resists occasional frosts of the order of -15°C (5 °F), some natural habitats undergoing long periods of cold.
It forms a small tree of 7 to 8 m (23 to 26 ft 2 in), at most 10 m (32 ft 10 in) high, with 5 to 6 m (16 ft 5 in to 19 ft 8 in) spread, carried by a trunk which often becomes twisted with age. Its coppery bark is very decorative, especially in the rain which brings out its colour. It peels off in large flakes that fall to the ground, forming a litter layer at its foot. It also sometimes takes a bushy habit, like the group of mallees (Eucalyptus less than 10 m (32 ft 10 in) high developing several stems from the soil). This Eucalyptus has a significant ability to regenerate thanks to its lignotuber, an underground swelling rich in starch, capable of emitting many shoots if the above-ground part of the plant is destroyed (typically by fire). The regrowth is denser than the original young plant. This characteristic is particularly interesting from an ornamental point of view, as it allows severe pruning, which limits the development of the plant, makes it branch well and stimulates the formation of juvenile foliage, which in many species, is more decorative than the adult foliage.
This is the case with the E. perriniana, whose juvenile foliage is one of the most beautiful in existence. The opposite leaves fuse at their base, thus taking an elliptical shape 3 to 8 cm (1.2 to 3.1 in) long by 5 to 8 cm (2 to 3.1 in) wide, encircling the young shoot from all sides. Visually, the stem seems to pierce a target made up of fused leaves, like the thread of a necklace passing through pearls. This amazing architectural design is magnified by the bluish colour of the leaves, which is absolutely beautiful. The adult foliage is more classic and takes a lanceolate shape, with leaves measuring up to 16 cm (6.3 in) long by 5 cm (2 in) wide, equipped with petioles and in an alternate position. In this species the juvenile foliage persists for a long time in the crown, sometimes the adult foliage does not appear at all, which has a visual advantage.
The flowering is relatively insignificant. Small white pompoms of about 1 cm (0.4 in) in diameter, formed by the stamens, group together in 3s in small axillary umbels. You have to be particularly patient, as it usually only occurs after about twenty years! In Australia, it occurs from January to March and under our climates, usually around August to September.
Eucalyptus perriniana is easy to grow and has the characteristic, unusual in this genus, of tolerating half-shade, even if it prefers a sunny exposure. Preferring neutral to acidic soils, it is moderately tolerant of limestone. Once well rooted, it can withstand dry spells, but will grow better in moist to wet soils, even accepting temporary flooding. A well-drained soil is however preferable, especially in winter. Its hardiness can go down to -15°C (5 °F), making it a very interesting species in most regions.

Eucalyptus perriniana is certainly one of the best choices for creating an exotic scene in the garden. Its limited size and its hardiness allow for planting in most situations. Its bluish foliage will create an astonishing contrast with that of Albizia julibrissin Summer Chocolate, which is cut to the point of earning it the nickname Mimosa of Constantinople. Evoking the tropics with its airy habit and pompom flowers, this small tree takes on dark purple to chocolate colours in summer. To complete this picture of coloured foliage, nothing is better than a golden bush like Choisya Goldfinger, a Mexican Orange with cut leaves and whose scent of white flowers betrays its membership of the citrus family.