New Zealand flax (Phormium tenax)

Present distribution

Scientific name:	Phormium tenax (J.R.Forst. & G. Forst)
Common name(s):	New Zealand flax

Map showing the present distribution of this weed.

Habitat:

Invades seasonal freshwater wetland (Carr et al. 1992). Dominates shrubland and rushland (Sorrell & Partridge 1999). Fairly frost hardy…moist conditions, medium drought tolerance, high salt wind tolerance (Burnie et al. 1997). Ditches, roadsides, streambanks (Richardson et al. 2006). Brackish swamps or on dry wind swept hillsides (Metcalf 1972). Rainforest (PIER 2009). Freshwater wetland (Carr et al. 1992). Native forest and disturbed grassland (PIER 2009). Tolerate occasional flooding with saline water (PIER 2009).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Pasture irrigation

Ecological Vegetation Divisions
Coastal; swampy scrub; freshwater wetland (permanent); treed swampy wetland; lowland forest; forby forest; damp forest; riparian; wet forest; rainforest; rocky outcrop shrubland; western plains woodland; basalt grassland; riverine woodland/forest; freshwater wetland (ephemeral); saline wetland

Colours indicate possibility of Phormium tenax infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

map showing the potential distribution of phormium tenax

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	They form fan-shaped clumps of tough leaves up to 3m tall and as wide (Macoboy 1986). The Phormium plant grows in bunches, or in groups of plants or shoots (Hector 1889). Stream banks (Richardson et al. 2006). High nuisance value. People and/or vehicles access with difficulty.	MH	MH
2. Reduce tourism?	Likely to restrict access to waterways (Macoboy 1986). Some recreational uses affected.	MH	MH
3. Injurious to people?	Causes allergies or is otherwise toxic to humans: No; No spines, burrs or thorns (PIER 2009). No effect, no prickles, no injuries.	L	MH
4. Damage to cultural sites?	Thick creeping underground stems (Richardson et al. 2006). Structural damage is unlikely. Moderate visual effect.	ML	M
Abiotic
5. Impact flow?	The water flowed unimpeded below a dense cover of New Zealand flax (Howard-Williams & Pickmere 1999). Phormium tenax is often used in restoration and revegetation plantings (WANF 2009). Little or negligible effect on water flow.	L	M
6. Impact water quality?	The water flowed unimpeded below a dense cover of New Zealand flax (Howard-Williams & Pickmere 1999). Phormium tenax is often used in restoration and revegetation plantings (WANF 2009). They form fan-shaped clumps of tough leaves up to 3m tall and as wide (Macoboy 1986). Likely to reduce light levels. Noticeable but minor effects in either dissolved 02 or light levels.	ML	M
7. Increase soil erosion?	Thick creeping underground stems (Richardson et al. 2006). Phormium tenax is often used in restoration and revegetation plantings (WANF 2009). Low probability of large scale soil movement; or decreases the probability of soil erosion.	L	MH
8. Reduce biomass?	“On rich “flax land” there are over two thousand bunches of Phormium to the acre, or one hundred thousand leaves (Hector 1889). They form fan-shaped clumps of tough leaves up to 3m tall and as wide (Macoboy 1986). Biomass may increase.	L	M
9. Change fire regime?	Creates a fire hazard in natural ecosystems: No (PIER 2009). Small or negligible effect on fire risk.	L	M
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Plains grassy woodland (E); CMA =Goulburn Broken; Bioregion = Central Victorian Uplands; VH CLIMATE potential. Native forest and disturbed grassland (PIER 2009). Forms dense thickets from which other species are excluded (BOTH 2009). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).	MH	MH
(b) medium value EVC	EVC = Riverine grassy woodland/ sedgy riverine (D); CMA =North East; Bioregion = Victorian riverina; H CLIMATE potential. Streambanks (Richardson et al. 2006). Forms dense thickets from which other species are excluded (BOTH 2009). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).	MH	MH
(c) low value EVC	EVC = Shrubby wet forest (LC); CMA = Corangamite; Bioregion = Otway ranges; VH CLIMATE potential. Native forest and disturbed grassland (PIER 2009). Forms dense thickets from which other species are excluded (BOTH 2009). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).	MH	MH
11. Impact on structure?	Forms dense thickets from which other species are excluded (BOTH 2009). Dominated shrubland and rushland (Sorrell & Partidge 1999). The presence of Phormium tenax significantly aids the establishment of native woody species (Reay & Norton 1999). Minor effect on >60% of the layers or major effect on < 60% of the floral strata.	MH	M
12. Effect on threatened flora?	In Hawaii the species forms dense thickets, principally in gullies in mesic areas below 300 m…In top 10 priority weeds in Hawai’i’s Kamakou preserve and is established in the Montane Ohia-Uluhe rainforest (PIER 2009). Not enough information.	M	L
Fauna
13. Effect on threatened fauna?	Phormium tenax is important in many ecological communities as a food source, and is often used in restoration and revegetation plantings (WANF 2009). Cattle are very fond of it. (Hector 1889). No reports of Phormium tenax threatening threatened fauna. Any population of a VROT spp is reduced.	ML	M
14. Effect on non-threatened fauna?	Phormium tenax is important in many ecological communities as a food source, and is often used in restoration and revegetation plantings (WANF 2009). Attract nectar feeding birds (Burnie et al. 1997). Cattle are very fond of it. (Hector 1889). No reports of Phormium tenax threatening threatened fauna. Minor effects on fauna spp.; minor hazard or reduction in habitat/food/ shelter.	ML	MH
15. Benefits fauna?	Attract nectar feeding birds (Burnie et al. 1997). Cattle are very fond of it. (Hector 1889). Forms a high % of diet of the Sambar deer in NZ (Kelton & Skipworth 1987). Provides an important alternative food source and/or harbour to desirable species.	ML	M
16. Injurious to fauna?	No spines, burrs or thorns (PIER 2009). No effect.	L	MH
Pest Animal
17. Food source to pests?	Phormium tenax is important in many ecological communities as a food source, and is often used in restoration and revegetation plantings (WANF 2009). Attract nectar feeding birds (Burnie et al. 1997). Cattle are very fond of it. (Hector 1889). Forms a high % of diet of the Sambar deer in NZ (Kelton & Skipworth 1987). Likely to provide some food to minor pests. Supplies food for one or more minor pest spp. (eg. blackbirds or environmental insect pests).	ML	MH
18. Provides harbour?	Not enough information. This rosette-like lily forms dense thickets from which other species are excluded (PIER 2009).	M	L
Agriculture
19. Impact yield?	This rosette-like lily forms dense thickets from which other species are excluded. Moloka'i, and the northern Hamakua coastline, Hawai'i (PIER 2009). Cattle are very fond of it. (Hector 1889). Agricultural/forestry/horticultural weed: No (PIER 2009). Unlikely to affect livestock, except possibly restricting access to water, and unlikely to affect crops. Minor impact on quantity of produce (eg < 5% reduction).	ML	M
20. Impact quality?	Cattle are very fond of it. (Hector 1889). Agricultural/forestry/horticultural weed: No (PIER 2009). Minor impact on quality of produce (eg < 5% reduction).	ML	M
21. Affect land value?	Cattle are very fond of it. (Hector 1889). Phormium tenax is important in many ecological communities as a food source, and is often used in restoration and revegetation plantings (WANF 2009). Agricultural/forestry/horticultural weed: No (PIER 2009). Can be harvested in for use in making ropes and paper (Wiki 2009). Unlikely to affect land value. Little or none.	L	M
22. Change land use?	Cattle are very fond of it. (Hector 1889). Agricultural/forestry/horticultural weed: No (PIER 2009). Little or no change	L	M
23. Increase harvest costs?	Cattle are very fond of it. (Hector 1889). Agricultural/forestry/horticultural weed: No (PIER 2009). If access to waterways is restricted control may be necessary which would increase production costs. Minor increase in cost of harvesting – eg slightly more time or labour is required.	ML	M
24. Disease host/vector?	The only two serious pests which attack them are a soft white scale insect and the leaf cutting flax moth; both are fairly easily controlled by spraying (Metcalf 1972). Small caterpillar causes a lot of damage (Hector 1889). Provides host to minor (or common) pests, or diseases.	M	M

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Propagate from seed or by division in spring (Burnie et al. 1997). Seed or division in spring (DT 2009). Germination is sometimes poor but should take place in 1 - 6 months at 15°C. Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination	MH	MH
2. Establishment requirements?	Full sun to light shade (DT 2009). Widely cultivated and now escaping into ditches and along roadsides and stream banks (Richardson et al. 2006). So adaptable that it can grow luxuriantly in brackish swamps or on dry wind swept hillsides (Metcalf 1972). Established in the Montane Ohia-Uluhe rainforest (PIER 2009). Can establish under moderate canopy/litter cover.	MH	MH
3. How much disturbance is required?	Invades seasonal freshwater wetland (Carr et al 1992). It grows in relatively intact native forest and disturbed grassland (PIER 2009). Establishes in relatively intact or only minor disturbed natural ecosystems (eg. wetlands, riparian, riverine, grasslands, open woodlands); in vigorously growing crops or in well-established pastures.	MH	MH
Growth/Competitive
4. Life form?	Perennial herb (Carr et al. 1992). Other.	L	MH
5. Allelopathic properties?	No allelopathic properties described. Allelopathic properties: No. (PIER 2009).	M	M
6. Tolerates herb pressure?	Forms a high % of diet of the Sambar deer in NZ (Kelton & Skipworth 1987). Many causes operate to destroy the Phormium: Cattle are very fond of it. (Hector 1889). If cattle have access to a field that has been cut, they will destroy the plants altogether, by drawing out the young leaves to chew the butts, of which they are very fond (Hector 1889). But for leaf damage only: “swamp flax, that had all the outer leaves taken off in January, had so many young leaves full-grown by the end of April that the casual observer would not have known that the plants had been cut at all (Hector 1889).	MH	MH
7. Normal growth rate?	New Zealand flax – dominated shrubland and rushland (Sorrell & Partridge 1999). Forms dense thickets (PIER 2009). Growth Rate: Average (LGG 2009). Moderately rapid growth that will equal competitive species of the same life form.	MH	MH
8. Stress tolerance to frost, drought, w/logg, sal. etc?	“Fairly frost hardy…permanently moist conditions” (Burnie et al. 1997). Virtually indestructible plants, thriving in wet or dry, hot or cold (at least -5 deg C) conditions, even exposed to salt spray (Macoboy 1986). Plants tolerate occasional flooding with saline water (PIER 2009). Highly tolerant of at least two of drought, frost, fire, waterlogging, and salinity, and may be tolerant of another. Susceptible to at least one.	MH	MH
Reproduction
9. Reproductive system	Rhizomes or seeds (Huxley & Griffiths 1992). Both vegetative and sexual reproduction.	H	MH
10. Number of propagules produced?	To 4.5 m…fruit a long capsule, to 10 cm; seeds many (Huxley & Griffiths 1992). "We estimate that over 10,000 seeds could be produced from one inflorescence stalk. (Note that this number is an extrapolation from a single collection at Puu Kolekole.)" (PIER 2009). Above 2000	H	MH
11. Propagule longevity?	The seed remains viable for about 12 months in normal storage (PIER 2009). Greater than 25% of seeds survive 5 years, or vegetatively reproduces.	L	M
12. Reproductive period?	Plants raised from seeds have never flowered at less than 6 or 7 years (PIER 2009). Will live for many decades (BBC 2009). Mature plant produces viable propagules for 10 years or more, or species forms self-sustaining monocultures.	H	M
13. Time to reproductive maturity?	Plants raised from seeds have never flowered at less than 6 or 7 years (PIER 2009). Greater than 5 years to reach sexual maturity, or for vegetative propagules to become separate individuals.	L	M
Dispersal
14. Number of mechanisms?	Water, wind (Carr et al. 1992). Discarded plants; seed, distributed by water, wind and possibly birds; rhizomes (pier 2009). Very light, wind dispersed seeds, or bird dispersed seeds, or has edible fruit that is readily eaten by highly mobile animals.	H	MH
15. How far do they disperse?	Very likely that at least one propagule will disperse greater one kilometre.	H	M

References

BBC (2009) BBC Gardening. Ask the gardener: Phormium tenax. Available at http://www.bbc.co.uk/lancashire/content/articles/2008/01/08/flax_feature.shtml (verified 05/2009).

BOTH (2009) Botany Hawaii: Alien Plants of Hawaii, UH Botany. Available at http://www.botany.hawaii.edu/faculty/cw_smith/pho_ten.htm (verified 05/2009).

Burnie G, Forrester S, Grieg D, Guest S, Harmony M, Hobley S, Hackson G, Lavarack P, Ledgett M, McDonald R, Macoboy S, Molyneux B, Moodie D, Moore J, Newman D, North T, Pienaar K, Purdy G, Silk J, Ryan S, Schien G (1997) Botanica Random House. Milsons Point, NSW.

Carr. G. W., Yugovic, J.V., Robinson, K.E. (1992) Environmental weed invasions in Victoria : conservation and management implications. Dept. of Conservation and Environment and Ecological Horticulture Pty Ltd.

DT (2009) Desert Tropicals. Available at http://www.desert-tropicals.com/Plants/Agavaceae/Phormium_Guardsman.html (verified 05/2009).

Hector, J. (1889) Phormium tenax as a fibrous plant. Command. New Zealand.

Howard-Williams & Pickmere (1999). Nutrient and vegetation changes in a retired pasture stream: recent monitoring in the context of a long term dataset. Science for Conservation. 114:41.

Huxley, A. and Griffiths, M. (1992). The New Royal Horticultural Society Dictionary of Gardening. Nature Publishing Group

Kelton, S. D. and Skipworth, J. P. (1987). Food of sambar deer in New Zealand. Flax swamp. NZ Journ. Ecol. 10: 149-152.

LGG (2009) Lets Go Gardening. Available at http://www.letsgogardening.co.uk/PD/Phormium.htm (verified 05/2009).

Macoboy, S. (1986). What flower is that? Londsdowne Press, Sydney.

Metcalf, L. J. (1972) The cultivation of NZ trees & Shrubs. A. H. & A. W. Reed.

PIER (2009) Pacific Island Ecosystems at Risk. Available at http://www.hear.org/pier/species/phormium_tenax.htm; http://www.hear.org/pier/wra/pacific/phormium_tenax_htmlwra.htm (verified 05/2009).

Reay, S. D. and Norton, D. A. (1999) Phormium tenax, an unusual nurse plant. New Zealand Journ. Ecol. 23:1, 81-85.

Richardson FJ, Richardson RG and Shepherd RCH. (2006) Weeds of the South-east. An Identification Guide for Australia. RG & FJ Richardson. Meredith.

Sorrell & Partridge (1999). Conservation values and management of Kongahu Swamp, Buller district. Science for conservation. 124: 50.

WANF (2009) Wangfang data. Biological flora of New Zealand. 10. Phormium tenax, harakeke, New Zealand flax. Available at
http://d.wanfangdata.com.cn/NSTLQK_NSTL_QK15858033.aspx (verified 05/2009).

WIKI (2009) Wikipedia – Phormium tenax. Available at http://en.wikipedia.org/wiki/Phormium (verified 05/2009).

Global present distribution data references

Australian Plant Name Index (APNI) http://www.cpbr.gov.au/cgi-bin/apni (26/03/2009).

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at http://www.anbg.gov.au/avh/ (verified 17/02/2009).

Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 07/05/2009).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 17/02/2009).

Integrated Taxonomic Information System. (2009) Available at http://www.itis.gov/ (verified 07/05/2009).

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (viewed 17/02/2009).

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2009) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 26/03/2009).

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