Buy Casuarina She-Oak Plants Online Australia — Hardy Native Trees for Screening, Erosion Control & Wildlife

She-Oaks — the genus Casuarina and its close Australian relative Allocasuarina — are among the most distinctive and ecologically important native trees in the Australian landscape. Despite their common name, She-Oaks are not true oaks: the name comes from the attractive, ray-patterned timber that resembles European oak, but weaker. They are not even closely related to oaks. What they are is uniquely Australian: trees and shrubs that have evolved extraordinary adaptations to thrive in the continent's harshest conditions — coastal sand dunes, rocky ridgelines, dry inland plains, and exposed windy headlands — where most other trees would fail.

The most striking visual feature of Casuarina and Allocasuarina is the foliage. What appear to be needle-like leaves are actually jointed, photosynthetic branchlets — the true leaves have been reduced to tiny scales along the branchlet joints. This adaptation reduces water loss to an absolute minimum, which is why She-Oaks handle drought, coastal salt spray, and exposed wind conditions with a composure that few other native trees match. The result is an airy, soft texture — somewhere between a conifer and a weeping willow — that creates a distinctive visual effect utterly unlike any other Australian native.

Our collection spans seven varieties covering an extraordinary range of garden and landscape applications — from the extraordinary Cousin It groundcover (one of the most conversation-starting plants in any garden) to the towering River She-Oak for large-scale screens and windbreaks, and the ornamental Rose She-Oak with its rusty bronze flowering display. Each variety has been selected by our horticultural team for proven performance and clear garden utility in Australian conditions.

An important note on Casuarina vs Allocasuarina

You will notice that some plants in this collection are labelled Casuarina and others Allocasuarina. This reflects a taxonomic revision made in the 1980s that split the original Casuarina genus — all Australian endemic species were reclassified into the new genus Allocasuarina (from Greek allos, meaning 'other'), while the true Casuarinas retained their name for the mostly non-Australian species. For practical purposes in Australian gardening, both groups are called She-Oaks, behave similarly, and are selected for the same garden uses. Our collection page uses the original common names (River She-Oak, Black She-Oak, Rose She-Oak) as these are how Australian gardeners search for and discuss these plants.

Nitrogen fixation — She-Oaks improve your soil

One of the less-known but most ecologically valuable characteristics of Casuarina and Allocasuarina is their ability to fix atmospheric nitrogen through a symbiotic relationship with the soil bacterium Frankia. Root nodules contain these nitrogen-fixing bacteria, which convert atmospheric nitrogen gas into plant-available ammonium compounds. This means She-Oaks not only thrive in poor, depleted, nutrient-thin soils — they actively improve those soils over time, increasing fertility for neighbouring plants and reducing the need for fertiliser inputs. This nitrogen-fixing ability, combined with the natural mulch created by fallen foliage needles, makes She-Oaks genuinely soil-building trees and an excellent choice for revegetation, erosion control plantings, and building fertility in depleted garden soils.

Our 7 She-Oak varieties — expert descriptions

Cousin It Casuarina glauca 'Cousin It' Best for: Groundcover, slopes, rockeries, path edging, feature Height: 30cm h x 1–2m w Habit: Prostrate, dense cascading curtain Key trait: Most iconic/distinctive groundcover in Australian nurseries

One of the most extraordinary and conversation-starting plants available in Australian nurseries — Cousin It is a prostrate, groundhugging selection of Casuarina glauca that produces a dense, cascading curtain of fine, bright green needle-like branchlets that drape to the ground from the centre of the plant, creating what many gardeners describe as a living shaggy rug or, inevitably, the famous Addams Family character. Growing to just 30cm in height with a spread of 1–2m, it is genuinely one of the most useful and most visually distinctive groundcovers available for Australian gardens. Our team considers it potentially the most useful groundcover on the market for sunny, well-drained positions. Fully coastal-hardy, drought-tolerant once established, and low-maintenance. Available from $25.95.

Shagpile Casuarina glauca 'Shagpile' Best for: Groundcover, slopes, erosion cover, mass planting Height: 30–50cm h x 1m w Habit: Low spreading, textured Key trait: Low-cost erosion groundcover

A slightly taller, more spreading companion to Cousin It — Shagpile grows to 30–50cm in height with a spread of around 1m, producing the same dense, textured, fine-needled coverage in a slightly more upright form than the completely prostrate Cousin It. Like all Casuarina glauca selections, it is coastal-hardy, drought-tolerant once established, and requires virtually no maintenance beyond occasional shaping if needed. Our team's pick for low-maintenance erosion cover on slopes and embankments, and for covering larger areas where Cousin It's very low profile might be less effective. Available from $19.95.

Greenwave Casuarina glauca 'Greenwave' Best for: Low screen, informal hedge, feature planting Height: To 1.5m h x 1.5m w Habit: Undulating, cascading, wave-form Key trait: Most ornamental glauca — flowing wave form

A medium-height selection of Casuarina glauca that grows to around 1.5m with a naturally undulating, wave-form habit — its branchlets arch and cascade in a fluid, organic pattern that creates a soft, flowing screen or feature plant. Greenwave is suitable for low informal hedging, screening panels, and feature planting where a more dynamic, naturalistic form is preferred over a clipped flat surface. Coastal-hardy and drought-tolerant. Available from $45.95.

River She-Oak Casuarina cunninghamiana Best for: Large screens, windbreaks, riverbank planting, tall feature Height: To 15–35m (fast-growing) Habit: Tall, weeping, fine-needled Key trait: Australia's iconic riparian tree — whispering foliage

The largest tree in our She-Oak collection — River She-Oak (Casuarina cunninghamiana) is a fast-growing, tall, graceful tree that can reach 15–35m at maturity with a slender, weeping habit of fine needle-like branchlets. In its natural habitat it grows along riverbanks, stabilising banks and improving soil through nitrogen fixation. In the garden it provides rapid, tall, dense screening, windbreak protection, and habitat for a wide range of birds and wildlife. Seeds are eaten by parrots and finches. The wind through She-Oak needles produces a distinctive soft whispering sound beloved in Australian landscape poetry and memory. Best for large gardens, screens, and windbreaks. Available from $19.95.

Black She-Oak Allocasuarina littoralis Best for: Backyard feature, mid-scale screen, coastal garden Height: To 10m h Habit: Rounded, bushy, medium-sized Key trait: Best She-Oak for suburban backyards

One of the smaller She-Oaks in our collection — Black She-Oak grows to around 10m with a naturally rounded, bushy form that makes it suitable for medium-to-large suburban backyards where a tall native feature tree or informal screen is wanted without the scale of River She-Oak. Its attractive dark bark — the source of the 'black' in its name — and fine, needle-like foliage create a distinctive year-round presence. Well-suited to coastal conditions and poor soils. Seeds and cones provide food and habitat for birds and small mammals. Available from $32.95.

Rose She-Oak Allocasuarina torulosa Best for: Feature tree, ornamental native, autumn-winter colour Height: To 15m h Habit: Upright, spreading, ornamental Key trait: Only She-Oak with major seasonal colour display

The most ornamental She-Oak in our collection — Rose She-Oak (Allocasuarina torulosa) is distinguished by its extraordinary rusty-brown to dark red male flowering display from March through June, which transforms the entire tree canopy into a warm, glowing amber-red colour during the autumn-winter flowering period. The deeply fissured, corky bark adds additional textural interest year-round. Growing to approximately 15m, it is an outstanding large feature tree that offers seasonal colour rarely seen in Australian native trees. Previously known as Casuarina stricta until the 1980s genus revision. From $32.95.

Swamp She-Oak Allocasuarina paludosa (or Casuarina glauca) Best for: Wet soils, waterway planting, poorly-drained positions Height: To 8–12m h Habit: Upright, dense foliage Key trait: Only She-Oak tolerating wet/inundated soils

The She-Oak specifically suited to wet, poorly-drained soils and waterway planting — Swamp She-Oak is the correct choice when other She-Oaks, which prefer free-draining conditions, would fail in persistently moist or seasonally inundated positions. Growing to 8–12m, it is used in waterway revegetation, wetland border planting, and gardens with poorly-drained soils where conventional She-Oaks cannot be reliably planted. Valuable for ecological restoration projects and challenging low-lying positions. $169.95.

 

How to grow Casuarina and Allocasuarina in Australia — expert care guide

She-Oaks are among the most resilient and low-maintenance native trees and groundcovers available for Australian gardens. Here is our complete care guide:

•    Position: Full sun produces the fastest growth and densest foliage. She-Oaks tolerate partial shade but growth slows significantly. All varieties are highly wind-tolerant and coastal-hardy — they are some of the toughest plants available for exposed positions, salt spray, and strong coastal winds. The Casuarina glauca selections (Cousin It, Shagpile, Greenwave) are particularly coastal-adapted.

•    Soil: Most She-Oaks prefer free-draining soil and will not tolerate persistently waterlogged conditions. Sandy, sandy-loam, and loam soils are ideal. They tolerate poor, nutrient-depleted soils very well — in fact, their nitrogen-fixing ability means they actually improve poor soils over time. The one exception is Swamp She-Oak, which is specifically adapted to wet and seasonally inundated conditions. Do not plant Swamp She-Oak in dry positions; do not plant other varieties in waterlogged positions.

•    Fertilising: She-Oaks generally require no fertiliser in most Australian garden conditions — their nitrogen-fixing symbiosis with Frankia bacteria provides adequate nutrition even in poor soils. If growth is very slow in the first year, a single application of a balanced native plant food in spring can help, but over-fertilising will not improve performance and is unnecessary.

•    Watering: Water regularly for the first 3–4 months after planting to establish roots. Once established, most She-Oaks are genuinely drought-tolerant. The Casuarina glauca groundcovers (Cousin It, Shagpile) in particular are remarkably drought-resistant once established. River She-Oak, despite its name, also tolerates seasonally dry conditions well in garden cultivation — it does not need a waterway to thrive.

•    Needle litter: She-Oaks shed fine needle-like branchlets continuously, which forms a natural mulch layer around the base. This is ecologically beneficial — it conserves moisture, suppresses weeds, and decomposes into humus. It is also aesthetically distinctive. For gardens where leaf/needle litter on paved surfaces is a concern, site She-Oaks thoughtfully, particularly for larger varieties near driveways or entertainment areas.

•    Pruning: She-Oaks generally require minimal pruning. Cousin It and Shagpile can be lightly shaped to maintain their desired spread. Larger tree varieties (River, Black, Rose She-Oak) are best left to their natural form — pruning large She-Oak branches is not recommended without arborist advice for larger specimens. Greenwave can be lightly trimmed to maintain its hedge shape.

•    Wildlife value: All She-Oaks provide exceptional wildlife value. The cone seeds are eaten by parrots (including the threatened Glossy Black Cockatoo, which depends on She-Oak seeds in many parts of its range), finches, and other seed-eating birds. The dense foliage provides nesting and roosting habitat for small birds and mammals. Older large trees provide perching sites for birds of prey.
•    Erosion control: She-Oaks are among the most effective plants for erosion control in Australian landscapes. The fine root network of Cousin It and Shagpile binds surface soil on slopes. River She-Oak's subsurface root network stabilises riverbanks. The continuously shed needle mulch protects the soil surface from water erosion and raindrop impact. For coastal erosion control, Casuarina glauca selections are the top choice.

Why buy She-Oaks from Online Plants?

•    30-day guarantee to grow on every plant
•    Australia's first and largest online nursery — 20+ years native tree delivery expertise
•    7 Casuarina/Allocasuarina varieties from groundcover to tall feature trees
•    Delivery to VIC, NSW, QLD, SA and ACT — metropolitan and regional areas
•    No minimum order
•    Free garden design consultation — call 0428 110 584 or email store@onlineplants.com.au

Frequently Asked Question - FAQs

What is a She-Oak and why is it called that?

She-Oaks are trees and shrubs in the genera Casuarina and Allocasuarina, belonging to the family Casuarinaceae. They are native primarily to Australia, with some Casuarina species also found in South-East Asia and the Pacific. The common name 'She-Oak' was given by early European settlers who noticed that the attractive timber — with its distinctive wide, dark rays and fine texture — resembled European oak in appearance and could be worked in similar ways, but was somewhat weaker ('she' being an old Australian colloquialism for inferior). The genus name Casuarina comes from the Malay word 'kasuari' (cassowary), as the drooping needle-like branchlets were thought to resemble the plumage of the cassowary bird.

What is the difference between Casuarina and Allocasuarina?

Both are commonly called She-Oaks and belong to the family Casuarinaceae. The distinction is a taxonomic one made in the 1980s: species endemic to Australia were reclassified into the new genus Allocasuarina (from Greek allos, 'other'), while true Casuarinas retained their classification for the mostly non-Australian species, including the widely planted Casuarina cunninghamiana (River She-Oak) and Casuarina glauca (including Cousin It and Shagpile). For practical garden purposes in Australia, both groups behave similarly, require the same care, and are sold and discussed as She-Oaks. The differences are botanical — primarily in cone structure and seed morphology — rather than horticultural.

Is Casuarina invasive in Australia?

No — Casuarina and Allocasuarina species are native Australian plants and are not considered invasive in Australia. They may naturalise beyond planting sites in some circumstances, but they are part of Australia's natural vegetation and wildlife systems, not environmental weeds in their home country. (The invasive concern applies specifically to Casuarina equisetifolia in Florida, South Africa, and parts of the Caribbean, where it was introduced and has become problematic — this is a completely separate context from Australian native garden planting.) Our collection contains exclusively native Australian species suited for Australian gardens.

Do She-Oaks fix nitrogen and improve soil?

Yes — this is one of She-Oak's most ecologically valuable characteristics. Casuarina and Allocasuarina form a symbiotic relationship with the soil bacterium Frankia, which creates nitrogen-fixing root nodules. These nodules convert atmospheric nitrogen into plant-available compounds, enriching the soil. This means She-Oaks thrive in poor, depleted, nutrient-thin soils where other trees would struggle — and they actually improve those soils over time, increasing fertility for neighbouring plants. The continuously shed needle foliage also creates a natural mulch that conserves moisture and decomposes into humus, further building soil health. This combination makes She-Oaks outstanding choices for revegetation, erosion control, and building soil fertility in degraded sites.

What wildlife does Cousin It and other She-Oaks attract?

She-Oaks are exceptional wildlife plants. The cone seeds are a critical food source for several parrot species, most notably the threatened Glossy Black Cockatoo, which is heavily dependent on Allocasuarina seeds in many parts of its range. Parrots and finches eat seeds from cones before they are released. The dense, fine foliage provides nesting and roosting habitat for small birds including wrens, honeyeaters, and finches. Older large trees provide perching sites for raptors (birds of prey). The continuous needle litter creates habitat for ground-foraging birds and insects. Cousin It's dense, low cascading form provides excellent ground-level cover for lizards, skinks, and small birds that nest at ground level.