Lime Lava Cushion Bush

Lime Lava Cushion Bush (Scleranthus biflorus 'Lime Lava') grows as a dense, undulating mound of tiny lime green leaves, no more than 10cm high and spreading to about 40cm. The surface is firm enough to look moulded rather than planted, which is why designers use it between rocks and pavers where a normal groundcover would look untidy. It is native to south-eastern Australia and New Zealand, and it asks for very little beyond drainage.

Why you'll love it

• A living cushion. The growth is so tight and even that the plant reads as a sculpted green form, holding its shape without clipping.
• Bright lime colour all year. The foliage stays a clear yellow green that lifts dark rock, gravel and charcoal pots.
• Genuinely low maintenance. No pruning, no feeding regime and almost no water once established. Neglect suits it better than attention.
• Cold and wind are no problem. Frost hardy, wind tolerant and drought tolerant, so exposed alpine style and coastal beds work well.

Where it works best

Rockeries and gravel gardens. This is its natural setting. The mounds spill over stone and echo the shapes around them, and the sharp drainage in a rockery is exactly what the roots want.

Groundcover and mass planting. Plant 30cm apart for a continuous cushion. At that spacing the mounds merge into an undulating green surface within two seasons.

Pots and borders. A shallow bowl or trough shows the domed habit better than a deep pot, and a single row makes a neat low edge along a path.

Growing Lime Lava Cushion Bush in Australia

Position and climate. Full sun to light shade. It belongs in cool temperate, warm temperate and Mediterranean gardens, so Melbourne, Hobart, Canberra, Adelaide, Perth and the southern tablelands are ideal. It dislikes sustained summer humidity, which rules out humid subtropical and tropical gardens where the centre of the cushion rots out.

Soil. Sharp drainage is the single requirement. Gritty, sandy or gravelly soil is ideal, and a gravel mulch keeps the roots cool while stopping the foliage sitting on damp ground. On clay, plant into a raised bed with coarse sand and gravel worked through.

Water and feed. Water regularly through the first summer, then only in prolonged dry heat. Feeding is rarely needed; a light application of slow release fertiliser in spring is enough if growth has stalled.

Pruning. None required. Pull out any patch that browns off in the centre and the surrounding growth will close over the gap within a season.

What to expect when it arrives

It is sold as tube stock, currently on backorder, and in 140mm pots in packs of ten. Tubes are small starter plants, best where you are covering an area and can wait a season. The 140mm plants arrive as formed cushions roughly the width of the pot, which is the quicker option for a rockery or a container.

Small plants travel well and may look slightly flattened on arrival before they lift again. Plant into free draining ground, water in, then ease right back. Delivered Australia wide, delivery from $29.95, and every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse plants suited to rockeries and gravel gardens
• A guide to choosing groundcover plants
• Compare the full groundcover range
• Plants for cool climate gardens

Common questions

How many plants cover a square metre?

At 30cm spacing you need about 11 plants per square metre. A pack of ten covers roughly one metre of continuous cushion.

Why did the middle of my cushion go brown?

Almost always humidity or moisture sitting in the crown. Improve drainage, use a gravel mulch instead of bark, and pull the dead section out so surrounding growth can close in.

Will it grow in Brisbane or Sydney?

Sydney can work in a raised, well drained position with good air movement. Brisbane and further north are too humid through summer for it to persist.