Until 1900 all flax used commercially came from swampy areas where the plant grew naturally. Between 1900 and 1920 many swamps where phormium already grew were drained and these areas have provided better quality leaf. After 1920 phormium was grown in plantations. It is not grown from seed. Fans are separated from existing flax-bushes and transplanted into rows from 4 to 6 ft apart. They grow to maturity in five years. The leaves are then cut about 6 in. above the ground and it is another four years before the plant can be cut again. Three varieties grown in 1961 were: ngaro and ngaire, two Maori varieties, and “S.S.”, an improved strain selected by a member of the Seifert family, well-known flax growers. The cut leaf is tied in bundles and transported to the mill where the fibre is separated from the fleshy part by a stripping machine. Then it is washed and spread on the ground or over fences for several days, to bleach. The dried fibre is next scutched, or scraped, by machine, to remove surplus vegetable matter, then pressed and baled.

Yellow leaf disease, a cause of failure in crops, was first reported in 1908. About 1920 large areas of phormium in the Manawatu district were destroyed by it. Many years of research into possible causes, viz., insects, fungi, bacteria, and virus, resulted in the discovery that “yellow leaf” was a virus spread by the phormium hopper. Prolonged flooding of plantations proved a method of exterminating the hopper and controlling the disease. There was evidence that some varieties, e.g., “S.S.” and “Tihore”, were resistant to “yellow leaf”.

At Foxton, the fibre is manufactured into woolpacks (2,700 tons of fibre for 1964), floor coverings (250–300 tons), carded hemp for the plasterers' trade, underfelt, and padding for upholsterers. A large rope manufacturing firm in New Zealand received 800 tons of phormium fibre in 1963. The phormium is mixed with imported sisal to make rope, hay-baling twine, binder-twine, and lashings. A higher percentage of phormium could be used in the manufacture of rope if the supply of good quality fibre was greater. Probably there is little likelihood of economic production of phormium fibre for export again, but there is scope for increased production for use in New Zealand.

by Jeanne Hannington Goulding, Botanist's Assistant, Auckland Museum.

• Letters and documents of L. Nattrass (1844–71) (MSS), Auckland Institute and Museum Library
• Phormium tenax as a fibrous plant, Hector, J. (1872)
• Historical Records of New Zealand, McNab, R. (1908)
• Phormium tenax, Atkinson, E. H. (1922)
• Agricultural Organisation in New Zealand, Belshaw, H., and others
• “Flax (Phormium tenax) or New Zealand Hemp,” Yeates, J. S. (1936)
• Report on a visit to New Zealand to study the Phormium industry, 1955, Moss, G. S. (Saint Helena: Solomon and Company) (1956).