Common name: New Zealand Flax, Flax, New Zealand Hemp, Flamin
Distribution and habitat: Phormium tenax is an evergreen perennial plant native to Phillip Island and indigenous to New Zealand, Norfolk Island and the Chatham Islands. It is an important fibre plant and a popular ornamental plant.
Phormium tenax is a coastal cover plant associated with significant habitat such as the breeding habitat for the endangered yellow-eyed penguin.
It is an invasive plant in many parts of the world and is proving a threat to sensitive floras.
Description: Phormium tenax are dramatic, architectural plants with a fountain of bold strap-like leaves and semi compact habit. The plant grows as a clump of long, strap like leaves, up to 80-90cm (31-35 inch) long, from which arises a much taller flowering shoot with sword-like form and dramatic yellow or red flowers. The leaves are coloured in tons of olive green, red, orange and bronze as it matures.
Phormium tenax are frequently used for spiky, sword-like form and a variety of colors, including greens, reds, copper and yellow, but are seldom recognized.
Gardening: Phormium tenax has medium to fast growing rate. They are perhaps the most versatile container grass-like plant to design with. It tolerates warm-temperate, temperate, cool-temperate climates – frost tolerant.
Avoid planting Phormium tenax during humid mid summer conditions. The base of the plant should be clear of mulch or soil build up to avoid plant rot. Remove spent leaves and old flower heads as required. It has low maintenance requirements once established.
Position: Phormium tenax tolerates a full sun to semi shaded position. It tolerates coastal conditions (it is tolerant of salt air) and moderate frost.
Soil: Suitable for most soil types. In more humid areas care should be taken to plant in well drained soils.
Water: They are generally tough plants that will endure hot dry positions once established, though their preference is for moist but well-drained soil. Apply mulch to reduce weed growth and keep the root zone cold and moist during dry periods, particularly for young plants.
Water as required for 8-13 weeks until established, then water as required. Once established it has a medium water requirement and responds to occasional deep watering .
Fertilising: Apply to the soil surrounding the plant a long term slow release fertilser at the end of winter. In the spring use a fertiliser rich in nitrogen and potassium to encourage the development of new vegetation and of flowerings.
Propagation: Phormium tenax is propagated from seed or clump division. The seeds remain viable for about 12 months when are stored adequately.
The seed is best sown as soon as it is ripe in a cold frame. Sow stored seed at the end of winter in a cold frame. Germination is sometimes poor but should take place in 1 – 6 months at 15°C (59°F). The seedlings are very variable. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Division in spring as growth commences. Larger divisions can be planted out direct into their permanent positions. Pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.
Toxicity: The blades of the plant contain cucurbitacins, which are poisonous to some animals and some of them are among the bitterest tastes to humans.
Leaf spotting fungus sometimes occur.
Treatment: To combat leaf spotting use a recommended fungicide according to label directions.
Slugs and mealybugs sometimes attack the plant.
Treatment: Use a recommended pesticide according to label directions.
Uses: Phormium tenax is planted in small gardens or in containers for color contrast. It is suitable for low maintenance gardens, rockeries and ornamental gardens. It is great around pools or ponds, as well as in pots. It works well in mass planting.
Phormium tenax is usually used as roadsides plants, mass plantings, feature plantings and plant gardens such as sunny edge of woodland garden, bog garden or cultivated beds.
Phormium tenax it is a great garden companion for plants like Pinus (pine), Cotinus (smokebush), Aster species.
Phormium tenax can be used as a colourful garden container in association with plants like Scirpus cernuus (Fiber optic grass), Heuchera hybrids (Coralbells), Pelargonium variegated hybrids (Variegated geranium), Citrofortunella microcarpa (Calamondin).
High: 80-90cm (31-35 inch)
Spread: 80-90cm (31-35 inch)
Hardiness zones: 9-10