Black she-oak

Sun

Full sun; tolerates light shade but develops a more open crown.

Water

Water regularly while establishing; low water needs once established, with occasional deep watering during prolonged drought.

Soil

Well-drained sandy, gravelly or loamy soil, preferably acidic to neutral. Tolerates poor soil and some clay where drainage is good; avoid persistently wet ground.

Height

20-40 ft (6-12 m), occasionally taller

Spread

10-20 ft (3-6 m)

Flowers

Usually autumn to winter: small reddish female flowers and inconspicuous brownish male flower spikes, generally on separate trees.

Foliage

Evergreen. Fine, dark green, jointed branchlets form an airy canopy. The true leaves are tiny scales arranged in rings around the joints.

Growth

Moderate to fast in suitable conditions.

Care needed

Low

• Drought tolerant
• Heat tolerant
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Hard

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   8 ft (2.4 m)

3. After 2 years

   9 ft (2.9 m)

4. After 3 years

   11 ft (3.3 m)

5. After 5 years

   14 ft (4.2 m)

About 16 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

Australia

Growth rate

Fast

• Water deeply through the first one or two growing seasons, allowing the soil surface to dry between waterings.
• Keep a broad mulch ring around young trees, leaving the trunk clear.
• Avoid routine feeding; on very poor soil, use a light application of low-phosphorus native-plant fertiliser.
• Stake only if the root ball moves in the wind, and remove supports once the tree is anchored.
• Plant away from drains, paving and buildings, allowing for its mature crown and root system.

Pruning. In late winter or after the main flowering period, remove dead, damaged or crossing branches and lightly correct the shape of young trees. Avoid topping or cutting heavily into old, bare wood.

Spring

Plant in cooler districts after the risk of hard frost has passed; water the root ball thoroughly.

Late spring

Check ties and stakes, and renew mulch without piling it against the trunk.

Summer

Deep-water young trees during dry weather; check soil moisture before watering again.

Autumn

Plant in mild-winter districts while the soil is warm and rainfall is returning.

Winter

Protect recently planted trees from unusually severe frost and check that the planting site drains freely.

Late winter

Remove damaged branches and make minor formative cuts on young trees.

• Use as a fine-textured specimen against a plain wall or an open lawn, with adequate clearance for its mature size.
• Plant in loose groups as a wind-filtering screen on a large site rather than as a tightly clipped hedge.
• Combine with banksias, wattles and native grasses in a dry Australian planting.
• Use its dark trunk and airy foliage as a backdrop to pale grasses and bold-leaved shrubs.

Garden styles it suits: Australian native, Coastal, Woodland, Wildlife garden, Low-maintenance and Desert / xeriscape.

Plant it with: Spiny-headed mat-rush, Kangaroo grass, Silver banksia, Coast banksia, Prickly Moses and Common everlasting.

Wildlife: The woody cones provide seed for some cockatoos, including glossy black-cockatoos where they occur naturally. The canopy offers shelter and nesting sites for birds; flowers are wind-pollinated rather than a major nectar source.

• Root rot and decline in wet soil: improve drainage before planting and avoid frequent irrigation around established trees.
• Frost injury on young trees: choose a sheltered position and protect young plants during severe cold; prune damaged growth after new growth shows what has survived.
• Scale insects: inspect stressed trees and treat accessible infestations with a labelled horticultural oil, following temperature restrictions.
• Sparse growth in deep shade: plant in a sunnier position rather than trying to correct the problem with fertiliser.

Not known to be toxic to people, cats, dogs or horses. Species-specific safety information is limited, so do not treat any part as food or allow pets to chew the hard cones and woody branchlets.

• Drooping she-oak (Allocasuarina verticillata)

  Usually has more strongly drooping branchlets and larger, broader cones. Its branchlet joints generally carry 9-13 leaf teeth, compared with 6-8 in black she-oak.

• Forest oak (Allocasuarina torulosa)

  Typically has conspicuously corky bark and finer, often drooping branchlets with 4-5 leaf teeth at each joint, rather than the usual 6-8.

• Swamp she-oak (Casuarina glauca)

  Often suckers into colonies and favours wetter ground. Its branchlet joints have many more leaf teeth, usually 12-20.

Allocasuarina means 'other Casuarina', referring to its separation from that genus, while littoralis means 'of the shore' and black she-oak refers to its dark bark.

Propagation. Grow from seed released by mature woody cones as they dry. Sow shallowly in a free-draining seed mix, keep evenly moist, and transplant seedlings while small to minimise root disturbance.

Accepted botanical name

Allocasuarina littoralis

Native range

New South Wales, Queensland, Tasmania and Victoria.

Measured

Average height 1000 cm.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.