Australian Gum (Eucalypt, Ironbark)
Eucalyptus species (MYRTACEAE)
Planting and Growing Australian Gum Trees
You’ll find everything you need to know to plant and grow Australian gum trees (eucalypt, ironbark) in the accompanying table’s tabs:
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- Flowers, foliage, seed caps, and seeds of Australian gum trees (eucalypt, ironbark)
- Growing conditions for Australian gum (eucalypt, ironbark)
- When to plant Australian gum (eucalypt, ironbark)
- How to plant Australian gum (eucalypt, ironbark)
- How to prune Australian gum (eucalypt, ironbark)
- Watering, fertilizing, and care of Australian gum (eucalypt, ironbark)
- Landscape uses of Australian gum (eucalypt, ironbark)
- Pest and disease control for Australian gum (eucalypt, ironbark)
Growing Australian Gum Trees
About 750 species of fast-growing, often aromatic, usually upright and spreading, sometimes shrublike, brittle, broad-leaved, evergreen trees, varying in height depending on the species, with juvenile leaves of varied shapes and blue green or green, leathery, round, oval, or dagger-shaped mature leaves and papery, persistent or deciduous bark.
The genus is divided into the bloodwoods, boxes, gums, peppermints, stringybarks, and ironbarks.
Australian Gum Planting and Care Guide
Flowers and Fruit
Distinctive green, pink, red, white, yellow, feathery and plumelike flowers in a woody bud cap, 1–4 in. (25–100 mm) long, in spring, form fragrant, blue green, leathery, oily, caplike fruit with many seed in summer.
Best Climates
U.S.D.A. Plant Hardiness Zones 7–10. Semi-hardy or tender.
Soil Type and Fertility
Damp, well-drained, sandy soil. Fertility: Average. 6.5–7.5 pH.
Where and How to Plant
Full sun. Space as recommended for species.
Proper Care
Easy–moderate. Keep damp until established; drought tolerant thereafter. Prune to shape and remove dead branches. Propagate by cuttings, seed.
About This Species
Good choice for accents, screens, walls, windbreaks in landscapes. Pest and disease resistant. Eucalyptus longhorn beetle and chlorosis susceptible in alkaline soils.
Common Species and Varieties of Australian Gum
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- Eucalyptus camaldulensis, red gum
- Eucalyptus cinerea, silver-dollar tree
- Eucalyptus citriodora, lemon-scented gum
- Eucalyptus ficifolia, red-flowering gum
- Eucalyptus globulus, blue gum
- Eucalyptus gunnii, cider gum
- Eucalyptus leucoxylon, white ironbark
- Eucalyptus microtheca, coolibah
- Eucalyptus moluccana, gray box eucalyptus
- Eucalyptus perriniana, spinning gum
- Eucalyptus polyanthemos, redbox gum
- Eucalyptus pulverulenta, dollar-leaved eucalyptus
- Eucalyptus punctata, gray gum
- Eucalyptus regnans, giant gum
- Eucalyptus resinifera, red mahogony
- Eucalyptus salubris, gimlet gum
- Eucalyptus sideroxylon, red ironbark
- Eucalyptus torquata, coral gum
- Eucalyptus viminalis, white gum
About Gum Trees
The Eucalyptus genus contains more than 750 species and varieties of highly varied, round- or narrow-crowned, broad-leaved, evergreen trees. They are native to Australia, New Zealand, and Polynesia.
All gum trees are tender and perform best in the mild-winter climates with hot, dry summers typical of their native range.
Gums are fast-growing, long-lived, open and branching or spreading trees or large shrubs that range in size from 10–100 ft. (3–30 m) tall and 6–40 ft. (1.8–1 m) wide. Many gums bear juvenile leaves that are different from their mature leaves, and most have showy inflorescences of caplike flowers with plume, brush, or crestlike, hairy stamens, in colors that range from light yellow to deep purple and red. They also have beautiful, mottled, often exfoliating bark that sheds in long, stringy patches.
They are resistant to most insects and diseases, except for the Eucalyptus longhorn beetle and gum psyllid, two introduced pests, and to iron chlorosis.
Large gums make bold statements when specimens are planted in open landscapes. Smaller gums are the right choice for accents, hedges, and screens.
Choose from among the popularly cultivated species above, at left.
Planting and Caring for Gum Trees
Gum trees, whether true gums, bloodwoods, boxes, peppermints, stringbarks, or ironbarks, are striking additions to the home landscape. Their foliage exudes a pungent scent—many are the source of essential oils—and they have crested or plumelike, fragrant flowers in late spring to early summer.
Plant eucalyptus trees in average, damp, well-drained, sandy soil with neutral acidity. Since all trees perform best when they are planted in unamended soil, test the acid-alkaline balance of your site prior to planting.
Gums grow best in slightly alkaline soils, 6.5–7.5 pH.
When you plant, carefully match the depth of the planting hole to the soil line of your tree. Backfill around the rootball with native soil and give the tree ample water through its first season, watering whenever the soil becomes thoroughly dry. Gums are very drought tolerant once they have become established and should be planted in sites where they will avoid receiving water from irrigation of turfgrass lawns or shrub borders.
Gums provide tall elements with strong form for those with gardens in mild-winter or arid climates. They require seasonal maintenance and care: their branches are brittle and subject to breaking in strong winds, and they drop bark, seed caps, flowers, and leaves that require raking. To balance these traits, they seldom require fertilizing, although leaf yellowing may signal the need for application of a fertilizer that contains buffering agents to increase soil acidity and trace nutrients needed to avoid chlorosis.
Water deeply after you apply such fertilizer to your gum trees.