Soap Plant

Chlorogalum pomeridianum is a fascinating tuberous perennial native to California but successfully grown by UK enthusiasts in sunny, well-drained borders. It is named the 'Soap Plant' because its fibrous bulb/tuber contains saponins once used by Native Americans as soap. It forms a large rosette of long, wavy-edged, grass-like leaves. From this center, a tall, branched flower spike rises in mid-summer, reaching up to 1.5 metres. The delicate, starry white flowers with green or purple mid-veins are unique in that they open in the late afternoon and remain open through the night to be pollinated by moths, closing by the following morning. In the UK, it requires a very sunny, warm position and exceptionally well-drained soil to mimic its native scrubland habitat. It is moderately hardy (H4) but must not sit in cold, wet soil over winter. It is an architectural curiosity that adds height and ethereal beauty to a dry garden or gravel bed.

Sun: Full sun.

Soil: Gritty, well-drained soil.

Hardiness: H4 — down to −10°C.

Flowering: Jun, Jul, Aug.