Phormium colensoi aka Mountain Flax

Phormium colensoi is an evergreen perennial from New Zealand. Its range includes North, South and Stewart Islands. Gardeners also call it mountain flax or small flax lily. The name Phormium cookianum refers to the same species. It belongs to the Asphodelaceae family. Wild plants grow from coastal cliffs to mountain slopes. They can dominate shaded slopes in the high country.

Plants reach about 4 feet (1.2 metres) tall. The reported spread is about 1 foot (0.3 metres). Their leaves stay green throughout the year. Flowers appear in July and August in the cited growing account. Each flower has both male and female parts. The flowers yield nectar that people can eat. Roasted seeds serve as a coffee substitute. The leaf bases also yield an edible gum. The roots have a strong purgative effect, so edible uses need care.

Choose full sun for the best match to its needs. The plant also tolerates light shade. It prefers rich loam but accepts a wide soil range. Sandy soils, clay and peat can all support growth. It accepts mildly acid, neutral and mildly alkaline ground. Keep the soil moist or wet. Bog gardens and damp beds suit its needs. It also grows at sunny woodland edges. Strong sea winds do not rule out coastal planting. The cited account reports hardiness to about 14°F (−10°C). It lists USDA zones 7–10.

The leaves provide a flexible fibre of good quality. Gum from their bases also serves as paper glue. These uses sit alongside its role in garden planting. Plants can grow among coarse grass cut back each autumn. Many named forms exist, and seedlings can vary a great deal. This species also crosses with Phormium tenax. Some garden hybrids have uncertain parentage.

Sow fresh seed in a cold frame when ripe. Stored seed can be sown there in February. Germination may be poor and can take one to six months. Keep young plants under glass through their first winter. Plant them out after the last expected spring frosts. Division offers another way to raise plants as spring growth starts. Large divisions can go straight into their final sites. The cited source records no known medicinal use. It does not flag this species as a weed.