This grower is sure of this plant identification.
Reliable and long-lived perennial which provides attractive vertical accents to a planting. Sword like leaves encircle slender wiry stems. Simple pure white flowers open progressively up each stem to culminate in a fine airy show followed by handsome black seedheads. Associates well with fine grasses like Stipa tenuissima in a gravel planting,though also useful as a feature plant in a pot which is how we use it at Lewis Cottage.
New Zealand satin flower
Libertia grandiflora (New Zealand satin flower). They are easily grown rhizomatous perennial, they are valued for the foliage, with decorative seed pods and flowers. The leaves are grass-like, brown-tipped and dark green, the flower are very small and are white.
They are moderately frost hardy, and they require a sheltered, sunny or partial-shaded position with well-drained, peat soil, that has plenty of moisture in the spring and summer. You can propagate by division in spring or from seed in spring or autumn.
Grown for their foliage, decorative seed pods and flowers. Suitable for coastal conditions.