Roundleaf Gum: A Distinctive Australian Tree for Warm Climates
Looking for a unique tree that brings a touch of the Australian outback to your landscape? Meet the roundleaf gum (Eucalyptus deanei), a medium-sized eucalyptus that’s caught the attention of gardeners in warm climates with its distinctive foliage and adaptable nature.
What Makes Roundleaf Gum Special?
This perennial tree gets its common name from its fascinating leaf transformation. Young roundleaf gum trees sport distinctive rounded, blue-green juvenile leaves that clasp the stem, creating an almost succulent-like appearance. As the tree matures, these rounded leaves gradually give way to the more typical elongated eucalyptus leaves we’re familiar with. It’s like watching a botanical makeover in slow motion!
The smooth bark adds another layer of visual interest, shedding in irregular patches to reveal a beautiful mottled pattern of cream, gray, and brown tones. When mature, roundleaf gum typically reaches 13-50 feet in height, making it a substantial presence without overwhelming smaller properties.
Where Does Roundleaf Gum Come From?
Originally native to eastern Australia (New South Wales and Queensland), roundleaf gum has found a new home in Hawaii, where it grows as a non-native species that reproduces naturally. In the United States, you’ll primarily find this tree thriving in Hawaii’s warm, subtropical climate.
Should You Plant Roundleaf Gum?
The decision to plant roundleaf gum depends on several factors. Here’s what you should consider:
The Pros:
- Drought tolerant once established, perfect for water-wise landscaping
- Unique foliage provides year-round visual interest
- Fast-growing shade tree option
- Attracts pollinators like bees when flowering
- Low maintenance once established
- Excellent windbreak potential
The Considerations:
- Non-native species that may not support local wildlife as well as indigenous plants
- Can be frost-sensitive, especially when young
- Requires significant space when mature
- May drop branches and bark, requiring occasional cleanup
Since roundleaf gum is non-native, consider exploring native alternatives that might provide similar benefits while supporting local ecosystems. In Hawaii, native trees like koa or wiliwili could offer comparable landscape value while supporting indigenous wildlife.
Growing Roundleaf Gum Successfully
Climate Requirements
Roundleaf gum thrives in USDA hardiness zones 9-11, making it suitable for consistently warm climates. It prefers subtropical to tropical conditions and doesn’t tolerate hard freezes, especially when young.
Ideal Growing Conditions
- Full sun exposure (6+ hours daily)
- Well-draining soil of almost any type
- Slightly acidic to neutral pH (6.0-7.0)
- Protection from strong winds when young
- Space for 25-40 foot spread at maturity
Planting Tips
Spring is the ideal planting time, giving your roundleaf gum the entire growing season to establish before any cooler weather. Choose a location with plenty of room for growth – this tree doesn’t like to be crowded and can become quite substantial over time.
Dig a hole twice as wide as the root ball but no deeper. The top of the root ball should sit level with the surrounding soil. Water thoroughly after planting and apply a 3-inch layer of mulch around the base, keeping it a few inches away from the trunk.
Care and Maintenance
Young roundleaf gum trees need regular watering for their first year, but once established, they’re remarkably drought tolerant. Water deeply but infrequently to encourage deep root development.
Pruning is generally minimal – remove any dead, damaged, or crossing branches, and you can shape the tree when young if desired. Be aware that eucalyptus trees are susceptible to the eucalyptus longhorned borer in some areas, so monitor your tree for signs of pest damage.
The Bottom Line
Roundleaf gum can be an attractive addition to warm-climate landscapes, especially if you’re drawn to its unique foliage and drought tolerance. However, as a responsible gardener, consider whether native alternatives might better serve both your landscape goals and local ecosystem. If you do choose to plant roundleaf gum, you’ll be rewarded with a distinctive, low-maintenance tree that brings a bit of Australian character to your outdoor space.
Remember, the best landscape choices are those that balance personal preferences with environmental responsibility – and there’s often a native plant that can give you the best of both worlds!
