I have a bit of a love/hate relationship with flax. On the one hand, I appreciate their ornamental value, their tenacious growth habits, their usefulness in traditional craftwork and their indispensability for native wildlife. On the other hand, they can get quite messy in the garden and their leaves are an absolute nightmare to mow around.
New Zealand flax are endemic strap-leafed, evergreen perennials that have been cultivated since Māori arrived for fibre, food, fabrics and weaving. Early European settlers gave it the common name of New Zealand flax, due to the similarity of the fibres produced to European flax, an entirely different plant species.
There are two species – Phormium tenax, the coastal flax, Māori name harakeke, has long strap leaves in shades of green, bronze and maroon. The orange-red flowers are held on a tall stalk above the foliage and the seed pods are upright. Phormium cookianum (also known as P. colensoi), the mountain flax or wharariki, is a smaller plant which has greenish-yellow flowers held horizontally on an arching flower stalk with the seed pods drooping down. Many different forms of these two species were selected over the centuries by Māori to provide different plant characteristics for each of the end uses.
In modern times, many colourful cultivars and hybrids of these two species have been created including:
• Alison Blackman, a compact variety with dark green leaves streaked with lemon and a narrow orange edge.
• Apricot Queen, with pale yellow leaves with green margins that tinge apricot in autumn;
• Cream Delight, with wide arching leaves with a cream-yellow stripe and green margins edged with red;
• Dark Delight, with beautifully arched dark reddish-brown leaves;
• Dazzler’ striped with deep maroon/purple and scarlet.
Flax are relatively tolerant to temperature extremes and a range of light conditions, they are quite drought resistant and will grow in most well-drained soils but prefer soils high in organic matter and acid to neutral soils. Although they will happily grow in low fertility soils, they grow best when fed occasionally with a fertiliser which is relatively high in phosphorus. They love a layer of mulch over the root system such as compost, well-rotted manure or composted pine bark.
Phormium can be divided every few years. The young plants, called “pups” or sometimes kiekie, should have several roots before being divided. Cut the foliage back to a fan about one-third of the original leaf length as the pups are separated. Planting, transplanting and dividing should be done in spring before the main leaf flush starts, and this is a good time to rogue out reverted plants (where the variegation has been lost).
And, finally, to keep these from making the garden look messy, or the leaves from destroying the lawnmower, plant flax near the mid border or even at the back of the border, rather than at the front. In winter, use a serrated knife or handsaw to remove the older leaves to keep the clump tidy.