- Mature height
- 1.5m to 2m (approx.)
- Mature width
- 1.5m to 2m
Casuarina glauca 'Green Waves' is a compact Australian native shrub form of the swamp oak, evergreen and densely rounded. What looks like fine needle foliage is actually a mass of slender green branchlets, and they move in the lightest breeze. The effect is soft and fine textured rather than prickly.
It handles full sun to part shade, salt wind, heavy clay, periodically wet ground and long dry spells once established. Growth is roughly 60 to 90 centimetres a year. It survives heavy and frequent frost without damage, and grows across temperate, Mediterranean, subtropical and coastal Australia with very little attention.
Typical uses are low screens, informal hedges, mass planting on banks, rural windbreak understorey and large pots. Coastal and exposed urban sites are where it earns its place, holding shape where softer shrubs burn. Councils and developers use it because it survives neglect and still reads as a considered planting.
Frequently Asked Questions
About Green Waves Sheoak
What is Green Waves Sheoak?
It is a compact cultivar of Casuarina glauca, the swamp oak, selected for a dense rounded habit rather than the tall tree form of the species. The fine weeping branchlets give it the look of a soft conifer, and it stays shrub sized, which makes it useful where the parent species would be far too large.
How big does it grow?
About 1.5 to 2 metres tall and 1.5 to 2 metres wide, and it holds that size without constant cutting back. Growth is around 60 to 90 centimetres a year, so it reaches useful height within two or three seasons. Trimming keeps it lower and denser where a hedge under 1.5 metres is wanted.
How far apart should I plant it for a hedge?
Plant 1 to 1.5 metres apart for a dense informal screen, or 80 centimetres apart for a tighter formal hedge that closes over sooner. For mass planting on a bank or in a garden bed, 1 metre centres give complete coverage within a couple of seasons. Stagger two rows where a solid block is needed.
Is it suitable for coastal positions?
Yes. Casuarina glauca is one of the more salt tolerant Australian natives, growing naturally on estuarine flats and behind foredunes. This cultivar takes salt-laden wind, sandy soil and reflected heat without burning. It is a sound choice for front line coastal gardens where most ornamental hedging plants fail within a season or two.
Is it frost tolerant?
Yes. It survives heavy and frequent frost without damage, which sets it apart from many salt tolerant shrubs. That combination of frost hardiness and coastal tolerance means it can be used in cold inland districts and on the beachfront alike. No winter protection is needed once the plant has been in the ground a season.
Can it grow in pots?
Yes. The compact size and fine foliage suit large containers, and it is often used in pairs beside entries or along balconies and rooftop terraces. Use a free-draining native potting mix and a pot of at least 50 centimetres. Water regularly through summer and feed with a low phosphorus native fertiliser.
How do I care for Green Waves Sheoak?
Water through the first summer, after which it largely looks after itself. Use a low phosphorus native fertiliser once in spring if growth needs pushing, and mulch to suppress weeds. Trim lightly two or three times a year for a formal shape, cutting into the soft outer growth rather than into bare old wood.