Eucalyptus robusta – Swamp Mahogany - Evergreen Trees Direct

Eucalyptus robusta – Swamp Mahogany

$265.00

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Size: 40cm/45L

40cm/45L 100L

Current Stock Height Guides

40cm/45L: 1.4m – 2.1m Approx.
100L: 1.7m – 3m Approx.

Height guide disclaimer: Height ranges are approximate only. As living products, plant heights naturally vary between individual plants, batches, and seasons. No guarantee is given that supplied plants will fall within the stated range. If minimum heights are required, you mustconfirm current batch heights with Evergreen Trees Direct prior to purchase. Variation in height is normal and is not grounds for return, refund, replacement, or compensation.

Mature Height & Width

Mature Height: 15m to 30m (approx.)

Mature Width: 8m to 12m

Eucalyptus robusta – Swamp Mahogany is expected to grow 1m to 1.5m per year (approx.).

Root Ball Dimensions

Use this as a reference when digging your planting hole. We recommend digging at least 10% wider than the dimensions below to encourage strong root development.

30cm Pot: 33cm (W) × 30cm (D)
40cm/45L Pot: 44cm (W) × 41.5cm (D)
50cm Pot / 70L Pot: 55cm (W) × 41.8cm (D)
100L Bag: 50.6cm (W) × 52.8cm (D)
150L Bag: 66cm (W) × 55cm (D)
200L Bag: 71.5cm (W) × 60.5cm (D)
300L Bag: 88cm (W) × 63.8cm (D)
400L Bag: 99cm (W) × 66cm (D)
500L Bag: 122cm (W) × 66cm (D)
750L Bag: 134cm (W) × 69cm (D)
1000L Bag: 146.3cm (W) × 71.5cm (D)
2000L Bag: 176cm (W) × 82.5cm (D)

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Shipping

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Contact

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Email: sales@evergreentrees.com.au

Phone: (03) 7042 3318

About Your New Eucalyptus robusta – Swamp Mahogany

Eucalyptus robusta is the eucalypt to plant where the ground stays wet. Swamp Mahogany tolerates periodic inundation and heavy clay that would kill most trees, while producing masses of cream nectar-rich flowers through winter and spring that are a critical food source for gliders, flying foxes and honeyeaters.

Eucalyptus robusta grows fast at 1 to 1.5 metres per year, reaching 15 to 30 metres tall and 8 to 12 metres wide, with thick spongy red-brown bark that persists to the small branches. It is a tree for parkland, rural properties, revegetation and large civic landscapes rather than suburban gardens.

This Australian native grows in full sun, tolerates light to moderate frost once established, and handles coastal exposure and salt-affected ground. Once away it needs no intervention, which is why it is a standard choice for large-scale habitat and shelterbelt planting.

Frequently Asked Questions

About Eucalyptus robusta

How big does Eucalyptus robusta grow?

Swamp Mahogany reaches 15 to 30 metres tall and 8 to 12 metres wide. It is a large tree and should be sited on acreage, parkland or revegetation sites rather than a suburban block.

Does Eucalyptus robusta tolerate wet soil?

Yes. This is its defining strength. It handles periodic waterlogging, heavy clay and seasonally inundated ground that would kill most other eucalypts.

How fast does Swamp Mahogany grow?

Very fast, at 1 to 1.5 metres per year in suitable conditions. It is often used where quick canopy cover or habitat replacement is needed.

When does it flower and what feeds on it?

Cream flowers appear through winter and spring. They are a key nectar source for honeyeaters, lorikeets, gliders and flying foxes, particularly in the leaner winter months.

Is Eucalyptus robusta an Australian native?

Yes. It is native to the coastal swamps and estuarine margins of eastern Australia and is widely used in habitat restoration along that range.

Is it suitable for coastal sites?

Yes. It tolerates coastal exposure and salt-affected ground well, which is why it appears naturally in estuarine and back-dune positions.

How far apart should I plant Eucalyptus robusta?

Plant 6 to 8 metres apart for a shelterbelt or revegetation planting, and at least 10 metres from buildings, services and paving given its eventual size.

Enriched Planting Mix (AO Certified)

$21.95

Enriched Planting Mix is a certified organic blend of Pure Magic Compost, composted animal manure, gypsum, composted coarse bark and a wetting agent, bagged in 30L. It is built to be dug through existing garden soil at planting time rather than used on its own, and the gypsum is what sets it apart from a plain compost.

Gypsum helps break up heavy clay so water and roots can move through it, while the compost and manure return organic matter and nutrient to tired ground. The coarse bark holds structure and keeps air around the root zone, and the wetting agent keeps moisture in the soil longer after rain or watering.

Use it when planting trees, shrubs, roses, fruit trees and exotic garden plants, particularly into clay. Dig a hole twice the width of the pot and 7 centimetres deeper, then mix roughly one third planting mix through the excavated soil. Spread 7 centimetres of that improved soil in the base before setting the plant in.

Frequently Asked Questions

About Enriched Planting Mix

What is Enriched Planting Mix made from?

It is a blend of Pure Magic Compost, composted animal manure, gypsum, composted coarse bark and a wetting agent. Each part has a job. The compost and manure supply organic matter and nutrient, the gypsum works on clay structure, the bark keeps air around the roots and the wetting agent holds moisture in the soil.

What plants is it suitable for?

It suits exotic garden plants, including roses, ornamental and deciduous trees, fruit trees, shrubs and perennials, and it earns its keep most on heavy clay sites. It is a planting mix rather than a potting mix, so its job is improving soil at planting time. Phosphorus sensitive natives are the one clear exception.

Is it safe for natives?

No, not for the phosphorus sensitive ones. The composted animal manure in this blend lifts phosphorus well above what Proteaceae such as Banksia, Grevillea, Hakea and Protea will tolerate, and the result can be leaf burn, dieback and plant death. Use the Native Potting Mix for those species, or plant them into unimproved local soil.

Is it certified organic?

Yes. It is a certified organic product with no chemical additives, which is why the manure and compost in it are fully composted rather than raw. That makes it sound around fruit trees and vegetable beds, and it means you are adding genuine organic matter to your soil rather than a synthetic conditioner.

How much do I need?

Work on roughly one third planting mix to two thirds of the soil you dug out of the hole. For a shrub out of a 200 millimetre pot that is only a few litres. An advanced tree going into a large hole will take considerably more. Judge the quantity by the volume of the hole rather than the size of the plant.

Can I use it in pots?

It is not a potting mix and should not be used on its own in a container. The blend is designed to be diluted through garden soil, and used straight in a pot it holds too much water and settles badly. For containers, reach for a premium potting mix, or the native mix if you are potting natives.

Does it need to be watered in?

Yes. Water the plant well several hours before you plant it, then water thoroughly again once the hole is backfilled and the soil firmed down. That first deep watering settles the improved soil around the root ball and drives out air pockets. Keep the water up over the first few months while the roots establish.

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Enriched Planting Mix (AO Certified)

$21.95

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Uses in my Garden

Avenue Planting
Council or Civic Landscapes
Rural Property Planting
Revegetation or Regeneration
Shade Tree

Eucalyptus robusta – Swamp Mahogany works in an:

Australian Native Garden – celebrates local plants with natural character.
Woodland Garden – layered, naturalistic design under dappled light.
Wildlife Garden – planting to attract birds, bees, and pollinators.

Is Eucalyptus robusta – Swamp Mahogany Evergreen or Deciduous?

Eucalyptus robusta – Swamp Mahogany is an Evergreen (foliage year round) Tree

Mature Height & Width

Mature Height: 15m to 30m (approx.)

Mature Width: 8m to 12m

Eucalyptus robusta – Swamp Mahogany is expected to grow 1m to 1.5m per year (approx.).

Growth Rate of Eucalyptus robusta – Swamp Mahogany

Eucalyptus robusta – Swamp Mahogany is expected to grow 1m to 1.5m per year (approx.).

They are considered to have a:

Fast Growth Rate

Frost Tolerance & Ideal Climate to plant Eucalyptus robusta – Swamp Mahogany

Is Eucalyptus robusta – Swamp Mahogany frost tolerant?

Eucalyptus robusta – Swamp Mahogany is Frost Tolerant – Can handle light to moderate frost once established.

Does Eucalyptus robusta – Swamp Mahogany Flower?

Eucalyptus robusta produces clusters of creamy-white fluffy flowers from winter into early spring. These nectar-rich blooms appear along the branchlets and provide a soft but valuable seasonal display that contrasts well with its dark green foliage and thick, fibrous bark.

Does Eucalyptus robusta – Swamp Mahogany flower?

Yes - Flowers

Flowering Period:

Winter
Spring

Flower Type:

Pollinator-attracting
Clustered

Flower Colour:

Cream

Is Eucalyptus robusta – Swamp Mahogany an Australian Native Tree?

Yes

Eucalyptus robusta – Swamp Mahogany is Native to Eastern Australia, from southern Sydney through coastal New South Wales into Queensland, where it grows naturally in swamps, floodplains, and wet coastal forests.

What is the Wildlife Value of Eucalyptus robusta – Swamp Mahogany ?

Its winter–spring flowering period supplies abundant nectar for honeyeaters, lorikeets, native bees and early-season pollinators. The dense evergreen canopy provides excellent shelter and nesting habitat for small birds, while the rugged bark supports insects and microfauna that enhance biodiversity in wetland and coastal gardens.

How much Sunlight does Eucalyptus robusta – Swamp Mahogany need?

Eucalyptus robusta – Swamp Mahogany will thrive best in:

Full Sun

Preferred Soil?

Eucalyptus robusta performs best in moist, well-drained loam or sandy loam soils and prefers slightly acidic to neutral conditions. Naturally adapted to wetter sites, it may struggle in very dry or compacted clay soils unless improved with organic matter to enhance both drainage and moisture retention. Keep soil consistently moist during establishment, then maintain deep, reliable watering as the tree matures to support healthy growth, winter flowering and long-term resilience.

Is Eucalyptus robusta – Swamp Mahogany Drought Tolerant?

Is Eucalyptus robusta – Swamp Mahogany Drought tolerant?

As a young tree it requires regular watering, and once established Eucalyptus robusta develops moderate drought tolerance. Naturally adapted to moist, swampy and coastal environments, it performs best with deep, occasional watering during dry periods to maintain strong canopy health and steady growth.

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How To Plant Your Eucalyptus robusta – Swamp Mahogany

Site: Choose a well-drained position in full sun to part shade with room for the canopy to develop.

Soil preparation: Enrich the planting area with quality compost and aged manure for a strong establishment phase.

Hole: Dig twice as wide as the root ball and the same depth.

Planting: Position level with the surrounding soil, backfill gently, firm in, then water deeply to settle the roots.

Recommended Planting Spacing For Your Eucalyptus robusta – Swamp Mahogany

Feature tree: 3 to 4 metres apart to allow the full canopy and form to develop.

Avenue planting: 3 metres apart for a uniform soft-textured avenue.

Eucalyptus robusta – Swamp Mahogany is expected to grow 1m to 1.5m per year (approx.).

Fast Growth Rate

Long Term Care For Your Eucalyptus robusta – Swamp Mahogany

Watering: Water deeply twice weekly through the first 12 months. Once established, reduce to once weekly in dry periods. Mulch helps maintain consistent moisture.

Mulching: Apply a 5 to 7 centimetre layer of organic mulch over the root zone, keeping it 5 centimetres clear of the trunk.

Pruning: Minimal pruning required. Light tip prune in late winter to maintain shape, and remove lower branches as the tree grows to develop a clean feature trunk.

Fertilising: Apply a slow-release native blend in early spring and again in autumn. Avoid high-phosphorus formulations as a precaution.

Pest and disease: Hardy against most pests and diseases. Occasional inspection in warm humid conditions is all that's needed.

Planting Your Eucalyptus robusta – Swamp Mahogany in Different Soil

Eucalyptus robusta performs best in well-drained sandy loam or loam with a slightly acidic to neutral pH. Adaptable to a wide range of soils when drainage is improved with organic matter.

Sandy soil: Free-draining and ideal. Mulch well to maintain consistent moisture.

Clay soil: Improve drainage with gypsum and organic compost before planting.

Loam: The preferred soil for steady root development and consistent growth.

pH: Slightly acidic to neutral preferred. Mulch with composted leaf litter to maintain levels naturally.

Frequently Asked Questions

Q: Can Eucalyptus robusta tolerate wet or waterlogged soil?
A: Yes, it thrives in moist to wet conditions, making it ideal for coastal and poorly drained sites.

Q: Is Eucalyptus robusta suitable for coastal or windy locations?
A: Yes, it tolerates coastal exposure and strong winds well.

Q: How fast does Eucalyptus robusta grow?
A: It has a fast growth rate, often exceeding 1m per year in optimal conditions.

Q: Does Eucalyptus robusta attract wildlife?
A: Yes, its flowers are highly attractive to birds, bees, and other pollinators.

Q: Can Eucalyptus robusta be used in shelterbelts or windbreaks?
A: Absolutely – it is well-suited for shelterbelts, windbreaks, and wetland buffers.