Eucalyptus globulus aka Tasmanian Bluegum

Eucalyptus globulus is an evergreen tree in the myrtle family. Its common names include blue gum and Tasmanian blue gum. Kew places its native range in southern Victoria and eastern Tasmania. It grows in moist valleys, hills and damp ground. Deep, rich soils support it in these sites. People grow it for timber, oil and garden display.

This fast-growing tree has a tall, straight trunk. Its narrow crown becomes rounder when it grows in open ground. Garden trees can reach 98 feet [30 metres] or more. The RHS gives a spread of 13–26 feet [4–8 metres]. Larger trees reach 180 feet [55 metres], with extremes of 230 feet [70 metres]. The bark sheds long strips that may gather around the base. Its surface can be white, cream, yellow, grey or reddish brown. Fresh bark beneath shows green, brown or cream tones. Slim, smooth twigs range from yellow-green to red.

The leaves have a strong scent and a leathery feel. Young leaves are oval and pale blue-white. Adult leaves are long, curved and shaped like a sickle. They may droop and have a blue coating beneath. Mature trees bear white flowers in spring or summer. Virginia Tech reports flowering in winter and early spring instead. Long, cream stamens form round blooms without petals. Bees and other insects pollinate them. The dry, heavy fruit forms a woody capsule. Fresh capsules look blue and warty, then turn brown.

Grow blue gum in full sun and a sheltered site. It needs fertile soil that stays moist but drains well. The RHS lists loam or sand, with acid to neutral pH. Protect it from cold winds that dry the leaves. Its UK hardiness rating is H3, suited to mild coastal areas. PFAF lists USDA zones 9–11. Frost can harm young growth, even on older trees. The RHS suggests coastal gardens and planting in beds or borders. Its bark and blue young leaves give it garden value.

Gall wasps and eucalyptus suckers may attack this tree. Silver leaf, honey fungus and oedema can also cause problems. PFAF flags some potential for weed growth. Leaf oil supplies flavouring, scents, cleaners and insect repellents. It also appears in cold remedies and has traditional medicinal uses. These uses do not make the raw leaves safe to eat. Swallowing the concentrated oil can cause severe poisoning or death. Contact with the plant may also cause a skin rash.