tree

River She-oak

Casuarina cunninghamiana

The Story

Plant Bio

Casuarina cunninghamiana, the river she-oak, is a fast-growing evergreen tree native to eastern and northern Australia, reaching heights of up to 115 feet. It features a straight trunk and graceful, weeping branchlets of jointed, pine-like green cladodes that perform photosynthesis in place of true leaves.

This dioecious species produces tiny, brownish-yellow male flower spikes at the branch tips, while female trees bear small, vivid red clusters on short side stems. The dense, needle-like foliage and aggressive, water-seeking root system make it highly effective for erosion control along banks, though it is invasive in parts of the southern United States.

Uses & Benefits:

Features a graceful, weeping habit with fine, pine-like foliage that rustles softly in the wind.

An exceptional windbreak and soil stabilizer for riverbanks and erosion-prone slopes.

Provides valuable roosting and nesting cover for local birds, though it lacks nectar for pollinators.

Essentials

At a Glance

Plant Type

Tree

Height

1380"

Width

590"

Light

Full Sun, Partial Sun

Zones

8, 9, 10

Water

Medium

Humidity

High

Lifespan

Long

Native To

Australia

Toxicity

Non-toxic

Bloom period

Late winter – Spring

In flower about 4 months of the year

Planting

How to Grow

Select a planting site in full sun with moist, well-drained sandy loam or alluvial soil.
Dig a hole twice as wide as the root ball and of equal depth, ensuring the root flare sits level with the surrounding soil.
Water deeply immediately after planting to settle the soil, and maintain consistent moisture during the first growing season.
Avoid applying any fertilizer, as the tree is adapted to low-nutrient soils and supplemental feeding produces weak, structurally unsound wood.

Pro Tip

Never prune back into old, bare wood, as this species lacks dormant buds on mature timber and will fail to reshoot.

Keep It Thriving

Care Guide

Do

Water young trees regularly until their deep root systems are fully established.
Plant well away from septic lines, foundations, and swimming pools to avoid damage from aggressive roots.
Maintain a clear zone around the base of young specimens to protect them from lawnmowers.

Don't

Do not fertilize, as excess nutrients cause rapid, weak growth prone to wind damage.
Do not prune into old, leafless brown wood, which causes permanent dieback.
Do not plant in highly alkaline or calcareous soils where the foliage will become chlorotic.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Mulch
Pest Check
Propagate
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Erosion ControlWindbreakPrivacy ScreenShade Tree

Companion Plants

Taxodium distichum Salix nigra Cephalanthus occidentalis

Multiply

Propagation Methods

Good to Know

Common Questions

River She-oak questions

What zones can River She-oak grow in?

River She-oak is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is River She-oak deer resistant?

Not reliably. Deer may browse River She-oak, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does River She-oak bloom?

River She-oak typically blooms in late winter through spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does River She-oak need full sun?

River She-oak does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is River She-oak drought tolerant?

Yes — once established (usually after the first full season), River She-oak handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.