Eucalyptus globulus Labill. subsp. globulus

blue gum, southern blue gum, Tasmanian blue gum

Australia: widespread in eastern New South Wales, eastern, southern and central Victoria, and Tasmania.

In New Zealand widely cultivated as a landscape tree of parks and gardens, or for shelter or in plantations; occasionally naturalised from nearby planted specimens.

Scattered records from throughout the North and South Islands of New Zealand.

• A tree to 70 m tall with bark smooth apart from base which has persistent slabs of rough bark, shedding in large strips and slabs; smooth bark white, cream, grey, yellowish or pale creamy orange, often with ribbons of shed bark in the upper branches.
• Young stems flanged and square in cross-section; waxy grey-white saplings and coppice very conspicuous.
• Long, glossy, green, adult leaves to 300 mm long and 30 mm wide, alternate, stalked, lanceolate to sickle-shaped.
• Juvenile leaves that are opposite and stalkless for many pairs, broadly elliptic to ovate to lanceolate, to 105 mm long and 50 mm wide, base stem-clasping, margin sometimes scalloped, usually upper surface green or slightly waxy grey-white and the lower surface copiously white-waxy.
• The single, large, usually stalkless, waxy grey-white, warty bud per axil (rarely in 3s), to 25 mm long and 20 mm wide, with funnel-shaped, ribbed base and flattened cap with central knob, is conspicuous.
• Fruit that are solitary, woody capsules, rounded or funnel-shaped, or square in cross-section, to 21 mm long and 27 mm wide, broad disc about level with the rim, with slight lobes, 4 or 5 valves about at rim level, partly covered by the disc lobes.

Tree to 70 m tall.

Bark smooth apart from base which has persistent slabs of rough bark, shedding in large strips and slabs; smooth bark white, cream, grey, yellowish or pale creamy orange, often with ribbons of shed bark in the upper branches. Hairs and adventitious roots absent. Young stems square in cross-section, and prominently winged, waxy grey-white.

Adult leaves alternate, stalked, blade lanceolate to sickle-shaped, 120–300 mm long, 17–30 mm wide, glossy, green, same colour above and below, hairless; side-veins at an angle greater than 45° to midrib, vein reticulation dense, intramarginal vein parallel to and well removed from margin, oil glands present; leaf stalk 20–35 mm long.

Juvenile leaves opposite and stalkless for many pairs, oblong to elliptic then ovate to lanceolate, 40–105 mm long, 22–50 mm wide, base stem-clasping, margin sometimes scalloped, usually different colour above and below with upper surface green or slightly waxy grey-white and the lower surface copiously white-waxy.

Flowers usually solitary in leaf axils (rarely in 3s), cluster stalkless or with a short, stout stalk 0–5 mm long; bud usually stalkless or very short-stalked, base of bud funnel-shaped, waxy grey-white, warty, with about 4 longitudinal ribs, 14–25 mm long, 14–20 mm wide, bud cap flattened with a central, raised conical tip; flowers (stamens) white; in mature open flowers, petals and sepals absent. Main flowering period: spring, but flowering may occur from winter through to summer.

Capsules woody, stalkless, rounded or funnel-shaped, or square in cross-section, 10–15(–21) mm long, 14–24(–27) mm wide, with about 4 longitudinal ribs, waxy grey-white, disc raised above the rim and lobed over the 4 or 5 valves which are usually near rim level.

The four subspecies of E. globulus have very similar bark, adult and juvenile foliage; buds usually with a warty, waxy-white, flattened cap with central knob; woody capsules varying from rounded to funnel-shaped; but they differ in number of buds or capsules in a cluster, and the size of buds and capsules.

• Eucalyptus globulus subsp. globulus usually has large, solitary, warty buds or capsules, but very occasionally they are in 3s. Capsules to 21 mm long, to 27 mm wide.
• Eucalyptus globulus subsp. bicostata and E. globulus subsp. pseudoglobulus have buds in 3s, but the former has sessile buds that are waxy grey-white, and a very short cluster stalk, with capsules to 22 mm wide, whereas the latter usually has the central bud on a short stalk, buds are often strongly ribbed, may or may not be waxy grey-white, the stalk of the cluster is broad and flattened, to 10 mm long and capsules are smaller, to 16 mm wide.
• Eucalyptus globulus subsp. maidenii has smaller, stalked buds in clusters of 7 that may or may not be waxy grey-white, the stalk of the cluster is flattened and long, to 25 mm, and smaller capsules to 10 mm wide.

Eucalyptus globulus is a forest tree species that is widespread in the ranges and subcoastal forests of eastern New South Wales, eastern, southern and central Victoria, and Tasmania. It is notable for the very conspicuous seedlings, coppice and young saplings with square stems and large, waxy grey-white, oblong to ovate, stalkless juvenile leaves. The trunks are mostly smooth and the adult leaves are large, bright glossy green and usually sickle-shaped.

Intergradation commonly occurs between E. globulus subsp. globulus, E. globulus subsp. bicostata and E. globulus subsp. pseudoglobulus where they come into contact, and with populations in southern Victoria it may be impossible to attribute a specimen to any particular subspecies.

Eucalyptus is a genus of nearly 800 species, most of which are endemic to Australia, with a few species extending to parts of Malesia and as far north as the Philippines.

• EUCLID
• Flora of Australia
• Flora of New Zealand Online (E. globulus subsp. globulus)
• Flora of New Zealand Online (species profile)
• Flora of New Zealand Online (weed profile)
• GBIF
• iNaturalist NZ
• NZPCN
• Plants of South Eastern New South Wales
• VicFlora: Flora of Victoria
• Weeds of Australia: Biosecurity Queensland