Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Harakeke and Wharariki

Few New Zealanders would fail to recognise harakeke, one of our most distinctive native plants. It is the principal weaving plant, and many weavers use named forms selected for leaf pliability, colour and fibre quality.

Harakeke

Māori names harakeke, kōrari (Northland)
Other common names flax, New Zealand flax, swamp flax
Scientific name Phormium tenax
Family Hemerocallidaceae (day-lily family)

Leaf strips are used in raranga, the plaiting of kete (containers) and whāriki (mats). Extracted fibre (muka or whītau) is used to make traditional kākahu (cloaks), and for cordage. Today, harakeke is also used in non-traditional ways to create original and exciting works of art.

Distribution

Harakeke grows throughout New Zealand, from sea level to about 1300 m in altitude. It is commonly found in lowland wetlands and along rivers, and in coastal areas on estuaries, dunes and cliffs. A hundred years ago, harakeke was much more abundant in many regions, but large wild stands today are diminished and scattered. Harakeke is often seen in gardens, is used widely in landscaping projects and in wetland restoration plantings, and as shelter belts on farmland.

Harakeke is said to be native also to Norfolk Island, though may have been introduced by Māori. The harakeke found on the subantarctic Campbell and Auckland islands was taken there by Māori and sealers in the 1800s.

Growth form

Harakeke is a herbaceous plant, meaning its growth form is soft, not woody. The robust, sword-like leaves are arranged in two adjoining sets around the growing point (rito) to form a fan. A unique feature of harakeke and related plants is that the lower third or so of each leaf is folded together along its midrib or keel. This creates a stiff, heavy butt.

Fans develop from the stout, fleshy underground rhizome or rootstock. The rhizome has many reddish yellow roots of varying lengths that extend laterally or downwards. Hundreds of fans can develop from the rootstock to create the flax bush. Because these offshoots are of the same genetic stock, they exhibit the same leaf and fibre qualities.

The number of fans produced in a bush varies a lot and is one of the characteristics that can help identify different weaving cultivars. For instance, the weaving cultivar 'Māeneene' quickly produces many fans set closely together. 'Ngaro', a tall variety with strong fibre, produces fewer, bulkier fans that are set wider apart.

In older plants the rootstocks branch, generally away from the centre, and new fans arise that may eventually create a ring around the original plant. Sometimes as the plant ages, the rootstock is exposed above the ground and new fans develop that are less thrifty, through receiving fewer nutrients and moisture. Some strains are more prone to this ‘perching’ behaviour (e.g. the weaving variety 'Paoa').

Most fans produce about eight mature leaves, four on each side of the rito, before they start to yellow and die off.

The leaves

The look and feel of the leaf is what draws a weaver to consider its worth for raranga or whatu. Harakeke leaves are variable in length (1–4 m), width (2–12 cm), and rigidity. Some bushes have stiff, upright leaves, others are softer and lax. The fibre bundles within the leaf run parallel to the keel. Sometimes these striations show clearly on the surface and the leaf feels rigid and tough. Other leaves are quite smooth to the touch. Leaf colour varies from blue-green, green, yellow-green through to bronze. The leaf underside is often glaucous, with a blue bloom like a plum.

Harakeke has coloured leaf margins and keel, with orange, red, brown and black being the most common. Colours can vary between young and old leaves, even within a bush. Coloured edges are narrow, thick or smudged. Young leaves in particular are sometimes smudged with colour (particularly reddish brown) at the tips.

Black-edged varieties are regarded by some weavers as having the best muka. The well-known varieties 'Kōhunga', 'Taeore' and 'Tapamangu' fall into this category. However, having a black edge and/or keel is not necessarily indicative of good fibre. There are excellent varieties with orange keels and margins, such as 'Arawa' and 'Makaweroa'.

Flowers

Harakeke flowers from late October through to February. Each spectacular flower stalk (kōrari) grows up to five metres tall from the centre of the fan, which dies after flowering has taken place. The new kōrari is heavy with sap, but dries out over the summer months and becomes very light.

Each kōrari has a group of peduncles, like little branches, that grow out from each side of the main stem. These peduncles branch further and carry clusters of dull red flowers.

Each individual flower has both male and female parts. The copious orange pollen is carried on a thin stalk that sticks up above the flower tepals (the fleshy ‘petals’). The pollen on a particular flower matures before the female parts below are ready to receive it.

The flowers are designed to be pollinated by nectar-feeding native birds – tūī, korimako (bellbirds) and pihipihi (waxeyes). Today, starlings, mynahs and honeybees are also frequent visitors.

When a bird visits a flower, it pushes its beak down into the flower tube to feed on the nectar. Pollen brushes onto the top of the bird’s head. The pollen is then transferred to the next receptive flower the bird visits – that is, a flower where the pollen has already been shed, and the stigma and style (female parts) have pushed forward to collect the pollen. The fertile pollen travels down the style to the ovaries at the base. The fertilised ‘eggs’ or ovules then develop into seed, contained in the pod that develops from the flower.

Cross-fertilisation

The flower bunches on a kōrari do not open all at once. Their opening spreads over about 6 weeks.

Ecologists John Craig and Ann Stewart carried out some experiments on harakeke reproduction and found that harakeke is largely ‘self-incompatible’. Seeds produced from outcrossed flowers (where pollen comes from a different plant) are much more numerous and are larger than those produced by flowers from different kōrari on the same bush. In turn, the latter seeds are larger and more viable than those produced from flowers on the same kōrari. Perhaps compounds exist in the flowers that inhibit the development of plants of the same genetic composition.

There are likely to be some changes in genetic composition though, even in the course of vegetative reproduction. For example, leaves of the striking variegated Parekoretawa will, on some fans over time, revert from yellow stripes to green.

How often does harakeke flower?

We still do not know for sure what triggers harakeke flowering. Bushes do not flower consistently each year, and even in a seemingly prolific year there are regional variations. It was thought that harakeke flowered well about every three years, triggered by high temperatures the previous autumn, but this is not always the case. The cues seem to be more subtle and are not yet well understood.

For instance, in the summer of 2007/08, most harakeke in the Orchiston reference collection at Manaaki Whenua, Lincoln, flowered. However, in a nearby trial block of 36 Orchiston cultivars of a similar age, not a single bush flowered. Included in this block are three plants of the cultivar ‘Paoa’, which over many years has been a consistent early flowerer, even in ‘bad’ flowering years.

Seeds

The seed capsules on harakeke form in the summer months, and are upright on the branches. This is the main feature that distinguishes harakeke from wharariki (Phormium cookianum). The pods can be short and stout, or long and narrow, and are triangular in cross section. Each pod contains dozens of black, glistening seeds. When the dry pods burst open, the seed is scattered, and can be carried by water and wind.

Propagation

Harakeke is easy to grow from seed, but to ensure a plant has the same properties as the parent bush, it is best to take a fan with some root material attached. Seedlings also take longer to mature, about 6–8 years. Plants grown from root stock take about half that time. See the link below for detailed information on establishing a pā harakeke – a planting of selected varieties for weaving.

Wharariki

Māori names Whararirki
Other common names mountain flax
Scientific name Phormium cookianum
Family Hemerocallidaceae (day-lily family)

Distribution

Wharariki is found throughout New Zealand, on cliffs and mountain slopes. It is more tolerant of lower temperatures than harakeke. Horticulturalists have developed many coloured ornamental forms that are widely used in gardens and landscaping projects.

Growth form

Wharariki is generally a smaller plant than harakeke, and the leaves are not as stiff. The leaves are usually less than 2 m in length and inclined to droop. Often there is little or no colour on the margins and keel of wild forms.

Leaves

The leaves are not as stiff because they do not contain such strong fibre bundles. It is more difficult to extract fibre from the leaves of wharariki, and it is weaker and finer. Because the leaves are softer, they are useful for learners. However, they would not make strong kete or whāriki, and with the lack of extractable fibre, wharariki plants are not used for muka.

Flowers and seeds

The flowers are greenish, with tones of orange or yellow (as opposed to the red of harakeke). The most obvious distinguishing feature is the seed pods. The pods of wharariki are long, narrow, and hang down, often with a twist. They curl and become papery with age.

Wharariki tends to flower earlier than harakeke, and more prolifically.

Hybridisation

Harakeke and wharariki are usually found in different environments. The two species can, however, interbreed easily (hybridise). Plant breeders take advantage of this when developing new ornamental strains. Recent molecular work carried out by Rob Smissen and Peter Heenan confirms that there are stable populations of wild hybrids. There may be other species (such as the Chatham Islands flax). Work on the extent of variation in flax species is ongoing.

Some of the well-known cultivars used by weavers are hybrids, such as 'Mawaru' and 'Wharanui'. Their leaves are light green and relatively soft. The pods have a twist and are not erect like harakeke or as long, curled and papery in old age as wharariki.

 

Prepared by Sue Scheele