Cushion Bun

Cushion Bun (Scleranthus uniflorus) forms a tight green dome barely 8cm high and about 40cm across, packed so densely it reads as moss over stone. It is grown for that shape, not for its flowers, which are insignificant. Once its roots are down it takes frost, wind and dry spells without complaint.

Why you'll love it

• A form nothing else quite gives you. Fine stems pack into a firm mound, so it reads as a solid green pillow, not a flat mat.
• It stays genuinely low. At 8cm high it never blocks a sightline or creeps over a path edge, and it holds that height for life.
• Tough where alpine looking plants usually struggle. Frost hardy, wind tolerant and drought tolerant once established, so exposed rockeries suit it.
• Close to no maintenance. Nothing to prune, stake or deadhead. Lifting the odd weed out of the cushion is the year's work.

Where it works best

Rockeries and gravel gardens. Set plants 30cm apart between stones and let the domes swell until they meet. The contrast between hard rock and soft cushion is the point of the plant.

Groundcover and edging. At the same 30cm spacing a run closes into a low undulating carpet along a path or bed edge, usually by the second season.

Pots and troughs. One plant fills a shallow bowl neatly, and raising it near eye level shows the domed surface properly.

Growing Cushion Bun in Australia

Position and climate. Full sun in cooler gardens, light afternoon shade where summers run hot. This is a cool temperate, warm temperate and Mediterranean plant. Humid tropical and subtropical summers are its weak point, because warm wet air inside the mound browns off patches.

Soil. Sharp drainage is not negotiable. Give it gritty, gravelly soil, or a cactus mix opened with coarse sand. On clay, plant into a raised bed or rockery pocket rather than flat ground.

Water and feed. Water through the first summer, then only in long dry stretches. It is drought tolerant, not waterlogging tolerant. A light dose of slow release fertiliser in early spring is ample; richer feeding makes the cushion loose and soft.

Pruning. None needed. Brush leaf litter off so debris cannot rot into the mound, and cut any brown patch back to clean tissue.

What to expect when it arrives

It is sold as tube stock or in 140mm pots in packs of ten. Tubes are small, a green button a few centimetres across, and they are the sensible buy when planting a rockery in numbers. The 140mm plants arrive as recognisable cushions and give the look in the first season.

It travels well, since there is no tall growth to snap. Plants are delivered Australia wide, with delivery from $29.95, and every plant carries our 30 day healthy plant guarantee. Expect a quiet few months while roots go down, then steady spread from the second spring.

Plant care guides and related reading

• Browse the wider rockery and gravel garden range.
• Compare it against other groundcover plants.
• See low growing options for paving and steppers.

Common questions

How far apart should I plant it?

Thirty centimetres apart. Any tighter and neighbouring cushions push against each other and lose the domed profile that makes the plant worth growing.

Can I walk on it?

No. This is a groundcover to look at, not a lawn substitute. The cushion crushes underfoot and recovers slowly, so keep it beside paths rather than in them.

Why has part of my cushion gone brown?

Nearly always moisture trapped in the mound after heavy rain, overhead watering or debris left on top. Clear it, improve the drainage beneath, and cut the dead patch out so healthy growth fills back in.

Will it cope in a humid subtropical garden?

Not reliably in the ground. Humidity rather than heat is the limit, so in warmer northern gardens grow it in a pot of gritty mix with air moving freely around it.