Cousin It

Cousin It (Casuarina glauca 'Cousin It') is a prostrate she oak that behaves less like a shrub and more like a slow moving green mat. It holds to about 300mm high and spreads to around 2m across, made up of fine soft weeping foliage that pours over rocks and walls instead of standing up. It is frost hardy, drought tolerant, salt tolerant and content in poor soil, a rare combination in a groundcover. Planted 1m apart it knits into continuous cover that shades out most weeds.

Why you'll love it

• Texture nothing else matches. The foliage is thread fine and constantly moving, so it softens hard edges in a way a clumping grass cannot.
• Genuinely tough. Frost hardy, drought tolerant, wind tolerant, salt tolerant and happy in poor soil. Once established it asks for almost nothing.
• Made for walls and slopes. It cascades over retaining walls, rock edges and pot rims, and the spreading habit holds soil on a bank.
• A native that suits formal gardens. Australian native credentials with a clean contemporary look that sits comfortably in a modern courtyard.

Where it works best

Groundcover and mass planting. Plant 1m apart for full cover. Each plant spreads to around 2m, so at that spacing the mat closes with useful overlap rather than leaving thin gaps in the second year.

Retaining walls and slopes. Set plants along the top of a wall about 600mm back from the edge and let the foliage spill over the face. On a batter it binds the surface and slows runoff.

Coastal gardens and pots. Salt and wind tolerance suit an exposed beachside verge, and in a wide bowl it gives a weeping curtain of foliage.

Growing Cousin It in Australia

Position and climate. Full sun gives the densest, tightest mat, and part shade produces a looser plant. It suits subtropical, warm temperate, cool temperate and Mediterranean gardens, and it is frost hardy, so southern and elevated districts are well within range.

Soil. Free draining is the only real requirement, and fertility is not. It performs in sand, gravel and poor compacted ground. On heavy clay, plant on a raised mound, then mulch 50mm deep between plants while they fill in.

Water and feed. Water deeply once or twice a week through the first summer, then only in extended dry spells. Being a she oak it fixes its own nitrogen, so feeding is largely unnecessary. If you do fertilise, use a native blend low in phosphorus.

Pruning and pace. Trim stray runners back in early spring, and shear the plant lightly if it thins in the centre after several years. Be realistic about speed: this is a slow to moderate grower, so allow two to three seasons at 1m spacing for the mat to close.

What to expect when it arrives

It is grown in six sizes. Tube stock and the 140mm pack of ten are the sensible economics for covering a bank, since 1m spacing means a lot of plants. The 200mm pack of six and 250mm pack of three suit a smaller area, while the 300mm and 400mm arrive already trailing for immediate effect at a wall edge.

Plants are packed to travel and delivered Australia wide, with delivery from $29.95. Advanced and large stock is freighted at cost. The foliage may look flattened on arrival and lifts again within a week or two. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse climbers and groundcovers
• See the full Australian native range
• Preparing a garden bed before planting

Common questions

How many plants do I need per square metre?

One per square metre, the 1m spacing recommended for full cover. For a faster close on a visible bank, tighten to 800mm and accept the extra plant cost.

Will it grow in a frosty garden?

Yes. It is frost hardy and suits cool temperate districts, unlike many of the trailing groundcovers it competes with.

Can I walk on it?

No. This is a planting to look at, not a lawn substitute. The fine foliage flattens and breaks under foot traffic.

Western Australia: this plant is listed as an environmental weed in WA, where it escapes from gardens into bushland. We do not recommend it for WA gardens. Please choose a local alternative.