This grower is sure of this plant identification.
Seed grown plants
Rengarenga, Rienga lily, Rock lily
Arthropodium cirrhatum (Rengarenga). This species is a tufted evergreen perennial. The leaves are lance-shaped to linear and grey-green. The flowers are produced in panicles of star-shaped white, purple or yellow blooms. It will grow to about 1m tall.
When grown under-glass use a loam based potting compost with full light. When grown outdoors grow in a fertile well-drained gritty soil, with full sun.
Grown for their flowers.