Eucalyptus gunnii

Where the species comes from

Eucalyptus gunnii occurs naturally only in Tasmania. Its habitats include poorly drained flats, valleys and plateaux, open woodland, and alpine soils rich in decaying plant matter among rocks. This cool, exposed background is unusual among widely cultivated eucalypts.

The common name cider gum refers to the sweet sap historically tapped from the trunk. Its rounded blue-grey leaves belong to the juvenile growth phase; mature trees develop peeling cream-and-brown bark and a crown of longer, narrower foliage.

Care for woody plants in containers

Temperature, watering and light: Because Eucalyptus gunnii comes from Tasmania, a well-established tree can withstand more cold than many other eucalypts. Young nursery plants still need time to adjust before severe cold, drying wind or intense sun. Even when coppiced for rounded juvenile foliage, cider gum retains the vigour and space requirements of a large outdoor tree.

Light, humidity and watering: Plant it in full sun and good airflow, using free-draining ground or a deep pot where moisture remains available without excluding air. Water a container plant as the surface begins to dry. Warm wind can dry a small root ball quickly. Although the species grows naturally in moist areas, its roots still need air and should never sit in waterlogged potting mix.

Feeding, repotting and leaf care: Feed moderately while new shoots are extending and avoid heavy late feeding that creates soft growth. Repot before the roots become tightly crowded, keeping the root ball as intact as possible. Cut back hard only when the plant is vigorous and well established. Protect the roots of a container plant from hard freezing and avoid abrupt moves between heated rooms and cold exposure.

Temperature, light and watering: A tree in the ground is considerably more frost-resistant than one in a pot. In winter, cooler temperatures and weaker light mean the roots use water more slowly, yet the evergreen leaves can still lose moisture in bright wind. Insulate the container during prolonged frost and check the root ball for both drought and persistent wetness.

When something goes wrong

Leaf loss on Eucalyptus gunnii can come from drought, crowded roots or waterlogging. Lift the container before watering. A very light pot and contracted mix need a deep soak. Heavy, wet compost with dull or dark roots needs time to drain before it receives more water. A densely rooted pot that dries again within hours has outgrown its present volume.

Elongated shoots with weaker blue-grey colour indicate insufficient sun. Move a soft nursery plant towards full exposure gradually, since sudden intense sun, freezing wind or severe cold can damage foliage that has not hardened. Localised crisp edges after wind are different from the progressive dieback of damaged roots.

Continuing branch decline above persistently wet roots is more serious than a short dry spell. Keep the container apart from healthy woody plants, remove dead growth with clean tools in dry conditions and prevent water collecting around the roots. Obtain a reliable diagnosis if dieback continues into healthy wood.

Hollow pink-brown galls on older foliage, followed by early-spring leaf fall, indicate eucalyptus gall wasp; established trees usually tolerate the damage. Raised corky oedema lacks an insect chamber and can develop when roots absorb more water than the leaves release, especially in cool, humid or low-light conditions. Even out moisture and restore airflow, since neither kind of old lesion disappears.

Eucalyptus gunnii is toxic to people and pets

• Keep this plant away from children, cats and dogs that may chew it.
• Its aromatic oils can irritate the mouth and digestive tract and may affect the rest of the body.
• Swallowing plant material may cause drooling, vomiting, stomach pain, weakness or unusual behaviour. Contact a veterinarian or medical professional if symptoms develop.

About the name Eucalyptus gunnii

Eucalyptus comes from Greek words meaning “well covered”, a reference to the operculum over each unopened flower bud. The epithet gunnii commemorates Ronald Campbell Gunn.

Charles Louis L'Héritier de Brutelle established the genus Eucalyptus in 1789 in Sertum Anglicum, page 18.

Joseph Dalton Hooker first described Eucalyptus gunnii in 1844 in London Journal of Botany, volume 3, page 499.