On distant shores: ’s natives as weeds abroad Murray Dawson1

New Zealanders love their native and in equal measure despise exotic weed invaders. New Zealand weed lists There are several weed and pest listings for It is sobering to consider that many of New Zealand’s New Zealand, including environmental weeds, weeds are from plants that were deliberately introduced National Pest Plant Accord (NPPA) and for horticultural purposes, and escaped from cultivation by Regional Pest Management Strategy (RPMS) plants. ‘jumping the garden fence’ into the natural environment and agricultural land. 328 species appear on the Department of Conservation consolidated list of environmental Plants such as blackberry, broom, gorse, old man’s beard, weeds in New Zealand (Howell, 2008). This listing and many others were introduced and propagated in includes three native species considered to be earlier times but quickly escaped cultivation to become environmental weeds when they establish and invasive, damaging natural areas and leaving a legacy become problematic outside of their natural ranges: that costs New Zealand millions of dollars annually in lost 2 Metrosideros excelsa (pōhutukawa), productivity and control measures . australis (pōhuehue) and crassifolium Weedy naturalised plants in New Zealand now outnumber (karo). the native species. A running total (www.nzflora.info) The National Pest Plant Accord (NPPA) is a indicates that there are more than 2370 fully naturalised nationwide list of invasive species banned from taxa compared with about 2230 indigenous representatives. sale, propagation and distribution. This Accord So what exactly is a weed? Weeds can be considered is a cooperative agreement between regional to be plants growing where they are not wanted (‘out councils, government departments with biosecurity of place’) and where they have detrimental effects. An responsibilities and the nursery industry. There are example given in An illustrated guide to common weeds of 163 species listed in the current NPPA manual (MPI New Zealand (Popay et al., 2010) is red and white clovers Biosecurity New Zealand, 2012) and under the which are valuable pasture components, but can also be 1993 Biosecurity Act, nurseries, garden centres and real nuisances in horticultural crops and in the garden. other groups and individuals can be prosecuted for growing, selling or displaying them. This explains why a few of our beloved natives can also be considered weeds within our own shores if they establish Regional Pest Management Strategies (RPMS) where they are not wanted and become troublesome. define priorities and goals of local councils to Furthermore, few people may realise that several manage or eradicate pests (both animals and plants) New Zealand native plants have escaped cultivation to within their regions. Each regional council has their become weedy in other regions of the world. individual list of pest species particular to their area for control and these are reviewed at up to five-yearly This article profiles a diverse range of these New Zealand intervals. native rogues both here and abroad and expands upon articles by the late Graham Harris (1998, 2002). Acaena novae-zelandiae (bidibid, piripiri, red bidibid) Acaena is a of about 100 southern hemisphere Some ‘biostatus’ terms used for plants in this species in the Rosaceae family. They are mat-forming article herbaceous plants with pinnate (i.e., they have • Native (= indigenous): a species that occurs leaves with more than three leaflets arranged in pairs). naturally in a country and was usually there prior Their fruit form a dense ball containing numerous seeds, to human arrival. and in some species the seed-heads form a burr which attaches to animal fur, feathers, clothing and shoes for • Endemic: a species restricted to a particular dispersal – to the annoyance of many a hiker. Some area or not found naturally outside of a country. weedy bidibids can be a serious problem in the wool of • Exotic: a purposefully or accidentally introduced sheep, and naturalisations in the early 1900s were through foreign species. contaminants in fleeces exported from and/or New Zealand. • Naturalised: an exotic plant that has established itself outside of cultivation. New Zealand is well represented with 18 indigenous species (of which 14 are endemic) – Acaena anserinifolia (hutiwai), A. buchananii, A. caesiiglauca (the glaucus bidibid), A. dumicola, A. emittens, A. fissistipula,

1 Landcare Research, PO Box 69040, Lincoln 7640, New Zealand; [email protected] 2 Previous estimates of the yearly cost of weeds to the New Zealand economy include the pastoral sector at $1.2 billion p.a. and the forestry industry at $90 million p.a. In 2003 it was estimated that giant buttercup (Ranunculus acris) alone cost the dairy industry $156 million in one year in lost production.

10 New Zealand Garden Journal, 2014, Vol. 17(1) A. glabra, A. inermis (the spineless appearance but are less suitable as bidibid), A. juvenca, A. magellanica, dense shelterbelts for which both A. microphylla (2 varieties), A. minor South American species have been (also 2 varieties), A. novae-zelandiae used. These two naturalised pampas (red bidibid), A. pallida (sand bidibid, grasses are environmental weeds, sand piripiri), A. profundeincisa, NPPA species and RPMS plants. A. rorida, A. saccaticupula and Conversely, one of our native toetoes A. tesca. A few of the indigenous is weedy abroad. species and cultivars are grown richardii, an endemic of the South as groundcovers, including Island of New Zealand (Fig. 2), is A. caesiiglauca, A. inermis ‘Purpurea’, regarded as an environmental weed and several selections of A. microphylla in where it has locally and A. saccaticupula. naturalised in western regions. This In addition, New Zealand has toetoe is also considered a potential two exotic species, of which one, environmental weed in New South A. agnipila (Australian sheep’s bur), Wales, and . is fully naturalised. This weedy bidibid occupies short dry grassland, A riverbeds, roadsides and waste places. It is distinguished by its and fruits being arranged on spikes, compared to all the native species which have their flowers and fruits in globular heads. Despite the species name ‘novae- zelandiae’, red bidibid is probably native to both New Zealand and Fig. 2 Austroderia (syn. ) richardii Australia (although some botanists (toetoe), growing in a natural New Zealand believe it to be an early Australian habitat near Cass, Craigieburn. Photo: Murray Dawson. import). Acaena novae-zelandiae (Fig. 1A–B) is considered a native Avicennia marina subsp. weed of unimproved pasture land and australasica (mānawa; mangrove) waste places in both countries. Avicennia is a mangrove genus of up to eight species assigned to the Acaena novae-zelandiae is the most family Acanthaceae (formerly in the common naturalised bidibid in Britain B Verbenaceae or Avicenniaceae)3. and Ireland, where it can displace native vegetation and become Fig. 1 Acaena novae-zelandiae (red bidibid). Avicennia marina occurs in both abundant on sparsely vegetated and A, mat-forming plant with seed-heads. northern and southern hemispheres, B, close-up of mature burr showing barbs on moderately disturbed lowland sites the ends of seed. Photos: Trevor James. with three subspecies recognised. and coastal sand dunes. Feathers of However, A. marina subsp. ground-nesting birds have been found (toetoe) australasica (mānawa; Fig. 3A–C) is so clogged with red bidibid seed- Toetoes are tall growing grasses with New Zealand’s only mangrove – and heads that the birds have starved. This long and attractive spikes. the most southerly mangrove in the species was possibly introduced to They belong to the (or to world – naturally occurring in the in about 1796 as a garden the Graminae if using the alternative North Island (from Parengarenga plant or, more likely, it established family name). Recently, all five Harbour south to Kawhia and Ohiwa accidentally from imported wool. The New Zealand native species were Harbours). This subspecies is shared first British record of it as a weed is in transferred from the related genus with the east coast of Australia 1901, from Devon. Cortaderia to Austroderia – A. fulvida, (, and A. richardii, A. splendens, A. toetoe Victoria) and Lord Howe Island. Red bidibid has also naturalised and the Chatham Island endemic in coastal areas in California and A. turbaria (Linder et al., 2010). As with other mangroves, A. marina is present in several other States subsp. australasica occurs in the including Hawai‘i. In New Zealand, these native toetoes intertidal zones of estuarine areas are encouraged to be planted and has vertical ‘breathing’ roots Through vegetative growth, one plant instead of the widely naturalised (called pneumatophores) projecting can cover up to 4–5 square meters South American pampas grasses from the mud at low tide. Mangroves under ideal conditions. Furthermore, which are retained in Cortaderia – play an important role in erosion one large plant can produce hundreds C. jubata (purple pampas grass) control and shoreline protection by of seed-heads and each can contain and C. selloana (pampas grass). slowing water flow and reducing wave 70–100 seeds. The New Zealand species have action. a more graceful and ornamental

3 Like several genera mentioned in this article, the taxonomic placement of Avicennia is contentious. Some classifications have placed it in the family Verbenaceae, and recently some botanists have placed it in its own family Avicenniaceae. However, recent phylogenetic (molecular) studies have suggested that Avicennia is derived from within Acanthaceae.

New Zealand Garden Journal, 2014, Vol. 17(1) 11 Carex species (New Zealand sedges) Carex is an extensive genus of the true sedges comprising nearly 2000 species in the Cyperaceae family. They are widespread in cold and temperate regions of the world, or in mountains of the tropics. Carex are perennial rhizomatous herbs, usually with 3-angled solid stems. A New Zealand is well represented Fig. 4 Carex albula (white sedge) cultivated with 79 indigenous species (of at Naturally Native plant nursery. Photo: which 68 spp. are endemic) and 26 Naturally Native NZ Plants Ltd. exotic species (of which 23 are fully naturalised4). Carex are popular for landscaping with species and cultivars suited to a wide range of environmental conditions, from wetland planting to dry areas, and B from shade to full sunlight. Ornamental New Zealand native Carex include the reddish-brown and upright form of C. buchananii, red and green cultivars of C. comans (e.g., C. ‘Frosted Curls’) and C. flagellifera, the orange-red and Fig. 5 Carex buchananii (Buchanan’s weeping form of C. testacea, and other sedge) cultivated in New Zealand. Photo: cultivated species including C. dissita, Phil Bendle. C. secta, C. tenuiculmis and C. virgata. Several New Zealand native Carex C are considered to be weeds of this Fig. 3 Avicennia marina subsp. australasica country where they can invade a (mānawa). A, plants growing in their estuarine variety of habitats (as suggested habitat showing pneumatophores. B, opposite by some of their common names), arranged leaves. C, close-up of flowers. including Carex breviculmis (grassland Photos: David Glenny. sedge), C. comans (maurea), In New Zealand, mānawa is the C. gaudichaudina (Gaudichauds dominant vegetation type in many sedge), C. geminata (rautahi), northern North Island harbours and C. inversa (creeping lawn sedge), estuaries. Increased sedimentation C. maorica (Māori sedge), C. pumila Fig. 6 Carex flagellifera (shining sedge) rates, especially from degradation (sand sedge), C. secta (pūrei) and cultivated at Naturally Native plant nursery. and deforestation of surrounding C. virgata (swamp sedge). Photo: Naturally Native NZ Plants Ltd. catchments, is causing the spread Four New Zealand endemic species of mangroves in some New Zealand are declared weeds under the harbours. This may impede access, Tasmanian Weed Management reduce water views, and decrease Act 1999 – Carex albula (where it property values. As a consequence, is called New Zealand hair sedge, some coastal residents want to remove or white sedge as it is known in plants (for which a resource consent New Zealand, after the bleached is needed) but unless sediment and white tips of the leaves; Fig. 4), nutrients are reduced this is likely to be C. buchananii (Buchanan’s sedge; ineffective (Green et al., 2003). Fig. 5), C. flagellifera (shining sedge; Dr R.L. Bieleski (2009) recounts the Fig. 6) and C. testacea (speckled unfortunate story of how propagules sedge; Fig. 7). In the past, these four Fig. 7 Carex testacea (speckled sedge) of A. marina subsp. australasica were were extensively planted on roadsides cultivated at Otari-Wilton’s Bush in New Zealand. Photo: Phil Bendle. collected in 1964 at Meola Creek, in Tasmania for soil binding and Auckland, exported, and planted in a beautification, and also sold widely Coprosma repens (mirror plant, salt marsh in Mission Bay of San Diego throughout Australia as ornamentals. taupata) and C. robusta (karamū) for research purposes. From there However, because of their weedy Coprosma is a genus of 100 species it subsequently spread to become a potential, the importation, sale and in the Rubiaceae (coffee) family. serious weed that has defied attempts distribution of all New Zealand native Coprosma species occur naturally at its eradication. sedges are prohibited in Tasmania. in New Zealand, Australia, Borneo,

4 Of the naturalised species, four are New Zealand environmental weeds – Carex flacca (blue sedge), C. leporina (syn. Carex ovalis; oval sedge), C. longebrachiata (Australian sedge) and C. lurida (sallow sedge). One species, C. pendula (drooping sedge, Otahuna sedge), is listed on the National Pest Plant Accord.

12 New Zealand Garden Journal, 2014, Vol. 17(1) Java, , the Hawaiian Coprosma repens (taupata; Fig. 8A– Coprosma robusta (karamū; Fig. Islands, the Juan Fernández Islands D) is an endemic low-growing 9A–C) is endemic to the North and and other islands of the Pacific or small bearing pairs of very South Islands, but is inclined to Ocean. Coprosmas have diverse shiny dark green leaves (hence its become weedy and has naturalised growth habits, ranging from prostrate other common name mirror plant). It locally on the . plants and divaricating with naturally inhabits the edges of coastal In Australia, karamū is an small leaves, to small with forest and seaside rocks on the Three environmental weed in southern relatively large leaves. They are Kings, North Island and northern Victoria and Tasmania, and is possibly dioecious (i.e., with separate male of New Zealand. also naturalised in New South Wales. and female flowers on separate However, it is now extensively plants) and female plants produce naturalised throughout the South australis berries that are orange, red or blue. Island, Stewart and Chatham Islands. (cabbage tree, tī kōuka) Cordyline is a genus of 15–20 New Zealand is very well represented In Australia, taupata is widely species of woody . with 54 indigenous species of naturalised in southern and central Botanists have puzzled over the which 50 spp. are endemic. They New South Wales, in many parts of correct placement of Cordyline are extensively cultivated as Victoria, in the coastal districts of which has consequently bounced ornamental plants and more than 140 south-eastern and southern South between a host of families including cultivars have been selected. Two Australia, in Tasmania, and in the the Agavaceae (now Agavoideae), New Zealand species have become coastal districts of south-western Asteliaceae, Dracaenaceae, weedy within our own shores and also Australia. Further afield, this species Laxmanniaceae and Lomandraceae. in other countries. is also naturalised in , Based on molecular evidence, Hawai‘i, California and South Africa. Cordyline is commonly now accepted in (subfamily Lomandroideae), although to the non-expert it seems incredulous that cabbage trees belong in the same family as the defining genus Asparagus! A Like some other genera mentioned A in this article, New Zealand is well represented by Cordyline, with five indigenous species (of which four are endemic) – C. australis (cabbage tree), C. banksii (Bank’s cabbage tree), C. indivisa (mountain cabbage tree), C. obtecta (Three Kings cabbage tree) and C. pumilio (dwarf cabbage tree). A further two species, B C. fruticosa (Pacific Island cabbage tree) and C. rubra, are exotic. However, it is the New Zealand endemic cabbage tree (tī kōuka and other common and Māori names), , that is the best known and has the widest natural B distribution throughout the North, South and Stewart Islands. C The iconic cabbage tree is one of the most widely cultivated New Zealand plants in Europe, Britain and the USA. They are hardy and tolerant of a wide range of conditions, and can be grown in containers or out in the open to provide a palm-like tropical effect in temperate regions of the world. More C than 30 cultivars have been named, including those with purple or red Fig. 9 Coprosma robusta (karamū). coloured leaves and green, cream, or D A, male flowers in dense clusters. Staveley, Canterbury. Photo: David Glenny. yellow striped variegation. Fig. 8 Coprosma repens (taupata). B, female plant in fruit. Pureora Forest Park, Cordyline australis is such a familiar A, male plant in flower. Photo: Phil Bendle. North Island. Photo: Murray Dawson. B, close-up of male flowers. Photo: Phil C, close-up of dark orange-coloured fruit. part of the planted landscape in the Bendle. C, female plant in fruit. Pureora Forest Park, North Island. south of England they have become Photo: Leon Perry. D, close-up of orange- Photo: Murray Dawson. known as Torquay palms, named coloured fruit. Photo: Leon Perry. after the seaside town in Devon.

New Zealand Garden Journal, 2014, Vol. 17(1) 13 Some trees are growing as far north Islands, south to Banks Peninsula on the island of Kaua‘i in 1891 and as Scotland, along the western coast (Fig. 11A–B) on the east coast, and became naturalised by 1912. It is most where the Gulf Stream tempers to Okarito on the west coast. Karaka common at Kōke‘e in the northwest of the climate. The seaside village of is probably naturalised on Raoul and Kaua‘i, where it was aerially seeded Plockton features an esplanade the Chatham Islands through these for reforestation in 1929. Along with of these tropical-looking ‘palms’ deliberate and historic Polynesian several other invasive plant species, (Fig. 10). plantings. Today, karaka is common karaka threatens the survival of one in cultivation in temperate regions of of Hawai‘i’s most endangered plants, New Zealand and other countries. the heau (Exocarpus luteolus, of the Because the fresh seed kernels Santalaceae family) which is endemic contain a lethal neurotoxin (Karakin), to Kaua‘i. Karaka also occurs on other the species has been banned islands of the Hawaiian archipelago from some amenity plantings and including Hawai‘i (Big Island), Moloka‘i kindergartens. and O‘ahu. The orange fruit is eaten by birds and feral pigs that disperse the seeds. Cotula australis (soldier’s button) and C. coronopifolia (bachelor’s Fig. 10 An avenue of Cordyline australis button) (cabbage trees) planted at the seaside Cotula is a genus of 50–80 species village of Plockton in Scotland. generally known as buttonweeds Photo: ‘Wojsyl’, via Wikimedia Commons and or water buttons in the daisy family reproduced under the Creative Commons Attribution-Share Alike 2.5 Generic license. (Asteraceae, or Compositae as it is also known). Despite being so widely grown, there are relatively few places in the world where cabbage trees have become weedy. In Australia, C. australis has naturalised in southern Victoria, south-eastern South Australia, and has sparingly naturalised in New South Wales. It has also naturalised at Salt Point A State Park in Northern California where the California Exotic Pest Plant Council listed it as a “wildland weed of secondary importance.” Corynocarpus laevigatus A (karaka, kopi) Corynocarpus is the sole member of its own family, the Corynocarpaceae. There are only five named species of these evergreen trees found naturally in the south-west Pacific: C. laevigatus of New Zealand, C. cribbianus of New Guinea and north-eastern Queensland, two subspecies of C. rupestris known only from a few localities in eastern Australia, C. dissimilis endemic to New Caledonia, and C. similis, the most widely distributed species, found B in Vanuatu, the Solomon Islands, Fig. 11 Corynocarpus laevigatus (karaka) B New Britain, New Ireland and the established at Raupo Bay, Canterbury, one of Fig. 12 Cotula australis (soldier’s button). Bismarck Archipelago. the sites on Banks Peninsula where karaka A, whole plant on the palm of a hand showing is naturalising outside of its natural range in its diminutive size. B, close-up of leaves and The New Zealand species, New Zealand. A, mature tree in an exposed flower-heads. Photos: Trevor James. Corynocarpus laevigatus (karaka), is habitat. B, oval shaped orange fruit. Photos: Murray Dawson. probably endemic to coastal forests of Cotula australis (soldier’s button; the northern half of the North Island. Few New Zealanders would realise Fig. 12A–B) is a low growing annual However, because the oval orange that karaka is a serious weed in with rosettes of feathery leaves fruits have been a traditional food the Hawaiian Islands where it is an and small, pale yellow, button-like source (as well as the seeds, which aggressive coloniser that forms dense flower-heads. It is indigenous to are poisonous unless detoxified), it shade which excludes other species, New Zealand and Australia and is also has been historically planted by the including some endangered native a weed of both countries, where it is Māori throughout the North and South plants. Karaka was originally planted widespread in suburban and disturbed areas, coastal sites, gardens, lawns

14 New Zealand Garden Journal, 2014, Vol. 17(1) and waste places. Soldier’s button is Bachelor’s button is a cosmopolitan from small pieces, which are easily now a widespread weed in temperate weed. It is widely naturalised in spread by birds, boats or fishing gear, parts of the Old and New Worlds. coastal areas of the USA (Alaska, and can form dense mats that out- Washington, Oregon, California, compete native aquatic plants. Another promiscuous and weedy Nevada and Arizona), in Canada buttonweed, Cotula coronopifolia (British Columbia, Quebec, Nova (bachelor’s button; Fig. 13A–B) is Scotia, New Brunswick and Prince also indigenous to New Zealand Edward Island), and many other and Australia, as well as southern countries. Africa. It has larger flower-heads than C. australis and these are bright Crassula helmsii (Helms crassula, yellow. Cotula coronopifolia is salt New Zealand pygmyweed) tolerant and occurs on coastal sites, Crassula is a diverse and widely especially in shallow water, and also distributed genus of about 200 inland in wet and waste places. Its species of succulent plants in the dispersal is aided by the corky wings Crassulaceae family. A of the outer seed achenes which float New Zealand has 11 indigenous in water. species (of which seven are endemic) and 20 exotic species (of which six are fully naturalised). Crassula multicava subsp. multicava (fairy crassula), a native of South Africa, is among most widespread in New Zealand. Fairy crassula grows on bare, exposed surfaces such B as rocks, concrete walls, banks Fig. 14 Crassula helmsii (Helms crassula). and cliff faces. It is classed as an A, plant showing mat-forming habit. B, close- environmental weed, an NPPA up of flowers. Photos: Trevor James. species and also subject to Regional Ironically, in New Zealand C. helmsii Pest Management Strategy control. appears to be rather uncommon with New Zealand has contributed one a patchy distribution throughout its of its own native crassulas as a natural range. It is known only from serious weed in other countries. the West Coast of the South Island Crassula helmsii (Helms crassula; between Karamea to just south of Fig. 14A–B) is a perennial, Haast. decumbent and mat forming herb, Dichondra repens found in shallow pools of fresh (Mercury Bay weed) water or in damp usually shaded Dichondra is a genus of perhaps A places. It has often been treated as nine species of prostrate, perennial, indigenous to both New Zealand and herbaceous plants, with creeping Australia. However, it may instead stems in the Convolvulaceae family. be endemic only to New Zealand because representatives there are Two species (Dichondra brevifolia apparently smaller and more delicate and D. repens) are indigenous (non- than Australian material. DNA and endemic) to New Zealand, and one chromosome evidence also suggest (D. micrantha) is fully naturalised. that Australian plants might be a Dichondra repens (Fig. 15A–C) is separate species. indigenous to New Zealand (Three It would appear that it is the Kings, North, South and Chatham New Zealand plant which has Islands), many parts of Australia naturalised in the UK. C. helmsii was (Queensland, New South Wales, first introduced there in 1927, was Victoria, Australian National Territory, recorded as naturalised in 1956, and Tasmania, South Australia and became fully established from 1970. It ) and probably is now regarded as a serious weed in Norfolk Island. It is commonly known the UK, and is one of five introduced as Mercury Bay weed in New Zealand aquatic plants banned from sale there and kidney weed (after its kidney from April 2014. This is the first ban of shaped leaves) in Australia. its kind in that country. C. helmsii has B Mercury Bay weed is found in also naturalised in western Europe grassland, lawns, scrub, crops, Fig. 13 Cotula coronopifolia (bachelor’s and south-eastern USA (Florida, forest clearings and margins. It may button). A, population in flower.B , close-up North Carolina and Washington). of flower-heads. Photos: Trevor James. have been deliberately planted as Crassula helmsii was originally grown low maintenance ground cover to as an oxygenating plant for ponds replace grass lawns or it can establish and aquariums. It can regenerate spontaneously in lawns as a weed.

New Zealand Garden Journal, 2014, Vol. 17(1) 15 Mercury Bay weed has probably Dodonaea viscosa is New Zealand’s brunnescens and naturalised in many countries sole native species in the genus and, E. nummulariifolium (creeping including China, Japan, South Africa including seven subspecies and much willow-herbs) and the USA, although the synonym variability, it is also indigenous to There are 160–200 species of Dichondra repens var. micrantha for Australia and throughout the tropics Epilobium of the family. D. micrantha confuses exactly what and subtropics. They are erect or creeping herbs or species occurs where. In California, subshrubs that have a worldwide In horticulture, akeake is a hardy D. repens has escaped gardens to distribution, favouring temperate fast growing shrub or small tree become a localised weed throughout climates. that thrives in windy, dry and the state. full sun conditions. The purple New Zealand has 39 indigenous foliaged cultivar, Dodonaea viscosa species (of which 31 are endemic) and ‘Purpurea’, is very widely grown five exotic, fully naturalised species. (Fig. 16A–B). As reported by Metcalf Epilobium ciliatum (tall willow-herb), (1987), this cultivar was discovered in a native of , is a very New Zealand in the early 1890s, from common naturalised willow-herb in a wild plant growing on the bank of New Zealand, where it occurs in lake the Wairau River, Marlborough. and pond margins, swamps, drains, cultivated land and moist waste places. Two New Zealand endemic A creeping willow-herbs, Epilobium brunnescens subsp. brunnescens and E. nummulariifolium (Fig.17 A–C), are frequent weeds of potted plants and were carried abroad unnoticed in this manner.

A

B A

B C Fig. 15 Dichondra repens (Mercury Bay weed). A, plant showing prostrate habit. B B, close-up of kidney shaped . C, close- Fig. 16 Dodonaea viscosa ‘Purpurea’. up of flower. Photos: Trevor James. A, a mature tree planted as a seedling by the Dodonaea viscosa author in the mid-1980s. B, purple-coloured foliage. Photos: Murray Dawson. (akeake, hopbush) Dodonaea is a genus of about 70 Although this purple-leaved cultivar species in the Sapindaceae, the is of New Zealand provenance, it soapberry family. They have a was widely (but incorrectly) sold as C cosmopolitan distribution in tropical, a native selection in Australia. In Fig. 17 Epilobium nummulariifolium subtropical and warm temperate Western Australia, it has escaped (creeping willow-herb). A, plants showing regions of Africa, the Americas, cultivation and is invading areas of long fruit pods longitudinally split open and southern Asia and . By native bush. recurved. B, close-up of small flowers with four deeply notched . C, close-up side far the highest species diversity is in view of seed capsule, split open to reveal Australia. seeds. Photos: Trevor James.

16 New Zealand Garden Journal, 2014, Vol. 17(1) Epilobium brunnescens subsp. have noted that this had been a Hydrocotyle tripartita, commonly brunnescens was first recorded fortunate escape for the region, as called Australian hydrocotyle after the in the British Isles in 1904, from the lacebark’s weedy tendencies were country from which it originated, is an Craigmillar, Edinburgh, and started its caught before it was widely available aggressive weed of lawns and waste main spread from the 1930s. It has to the public. places, particularly around Auckland. now invaded much of northern and It has been found as far south as western Britain – throughout all the Waikato and as far north as Kaitaia hills of northern England, Scotland, and is probably still spreading. Wales, Cornwall, and much of Ireland In New Zealand the most common excluding the central flat lands. It is endemic species that can be common as a garden weed on damp weedy are Hydrocotyle heteromeria walls, steps and gravel paths, and (waxweed pennywort), H. moschata in the wild in drainage ditch sides, (the hairy pennywort; Fig. 19A–C) and besides streams and ascending to H. novae-zeelandiae, which is quite high altitudes in the mountains. This variable with four varieties described low growing species can form patches (var. involucrata, var. lobulata, var. up to 2 m across and like other A montana and var. novae-zeelandiae). willow-herbs it produces abundant seed that can be dispersed by the Overseas, Hydrocotyle moschata is wind over long distances. It has an uncommon turf weed in the south been named among the 20 worst coast of California. introduced weeds in Britain where it is known as ‘New Zealand willow-herb’. Hoheria populnea (houhere, lacebark, ribbonwood) Hoheria is a genus of only six species of trees or large shrubs B (H. angustifolia, H. equitum, H. glabrata, H. lyallii, H. populnea and H. sexstylosa) in the Malvaceae family, and all are endemic to New Zealand. All species bear large, white, five- petalled flowers in profusion and (with the exception of the recently A described H. equitum of the Poor Knights and Hen and Chicken C Islands) are widely cultivated Fig. 18 Hoheria populnea (houhere). A, tree throughout New Zealand. Hoheria in flower.B , serrated leaves and flowers. glabrata, H. lyallii and H. sexstylosa C, close-up of flowers. Photos: Phil Bendle. have reasonable cold tolerance and Hydrocotyle moschata are therefore grown in Great Britain. (hairy pennywort) Hoheria populnea (houhere; Hydrocotyle or water pennyworts as Fig. 18A–C) is found naturally in they are sometimes called, is a genus coastal to montane forests in the of 75–100 species found in temperate B upper North Island, north of about and tropical regions worldwide. They Hamilton. Houhere is a fast growing were formerly placed in the Apiaceae tree attaining up to 11 m in height family, but are now in the . and able to colonise open areas. All species are prostrate perennials It is widely cultivated throughout with long creeping stems. They are New Zealand and is often found typically found in damp and shady naturalising throughout the North environments. Island, South, Stewart and Chatham Hydrocotyles are well-known Islands. troublesome weeds of grass lawns In California H. populnea is because of their tolerance to selective considered to be a potentially invasive broadleaf herbicides. They can also weed, and most of the mature cause problems in damp overgrazed trees that were growing at the then pastures in New Zealand, creating Strybing Arboretum in San Francisco low-growing dense mats that exclude C most other vegetation. (now known as the San Francisco Fig. 19 Hydrocotyle moschata (the hairy Botanical Garden) were removed New Zealand has 10 indigenous pennywort). A, cultivated plant showing its (sometime prior to being reported by species (of which nine are endemic) prostrate and creeping growth habit. Harris, 1998), along with their prolific B, close-up side view of leaf, showing and five exotic species (of which three densely hairy undersides. C, close-up of a seedlings. Californian authorities are fully naturalised). tiny flower-head. Photos: Trevor James.

New Zealand Garden Journal, 2014, Vol. 17(1) 17 Leptospermum scoparium Within New Zealand and away from also be at risk from encroaching (mānuka, tea-tree) these garden cultivars, native mānuka M. excelsa through possible inter- There are 87 species of provides nurse cover for regeneration hybridisation. For these (arguable) Leptospermum (family Myrtaceae), of native plant seedlings, stabilises reasons pōhutukawa is listed as an a genus centred in Australia, where the soil to help prevent erosion, environmental weed of New Zealand. most are endemic. Leptospermum and provides high value firewood, Pōhutukawa has a natural distribution scoparium (mānuka or tea-tree; essential oils and honey (Derraik, on sea cliffs and in coastal forest in Fig. 20A–C) is the sole New Zealand 2008). Despite these many useful areas north of Poverty Bay, on the indigenous species and is shared attributes, mānuka is a fast growing shores of the Rotorua lakes and on with mainland Australia and Tasmania coloniser that can be considered the Three Kings Islands. where it is less variable. More than weedy on New Zealand pasture land 150 garden cultivars have been (Fig. 20A). named from New Zealand mānuka In Hawai‘i, L. scoparium and the and have been selected for white, Australian species L. laevigatum were pink and red coloured flowers that both planted on Lana‘i during forestry are single or double and a range of efforts to stabilise eroding soils. After dwarf, prostrate and upright statures. a number of years, both species These ornamental cultivars are widely began to spread, with L. scoparium grown in many countries including becoming the more aggressive of New Zealand, Australia, South Africa, the two, forming monotypic thickets A the UK and the USA. that crowd out other plants. The first collection of it naturalising there was made in 1927. It is now found naturalised on Lana‘i, Kaua‘i, O‘ahu (Starr et al., 2003) and East Maui (Starr et al., 2004). Mānuka is still widely cultivated as an ornamental shrub in Maui but listed as one of Hawai‘i’s most invasive horticultural B plants (www.hear.org/hortweeds). Fig. 21 Metrosideros excelsa (pōhutukawa) A A 10-year old mānuka tree has been planted along the esplanade at Sumner, estimated to produce 8000 capsules Christchurch. A, mature tree in flower. containing an average of 400 seeds B, close-up of flowers. Photos: Murray Dawson. per capsule. Overseas, pōhutukawa is cultivated Metrosideros excelsa (pōhutukawa, in countries with mild climates and New Zealand Christmas tree) and in some places it has naturalised. M. kermadecensis (Kermadec M. excelsa has escaped from pōhutukawa) cultivation in the Western Cape Like Leptospermum, Metrosideros province of South Africa and has is another member of the Myrtaceae become a serious weed of the coastal that produces vast quantities of fine fynbos (a major ecosystem renowned seeds that are readily dispersed by for its diversity of native plant the wind. There are some 53 species species), where it is commonly called of Metrosideros, with a natural ‘New Zealand bottlebrush’. distribution across New Zealand, B New Caledonia, Hawai‘i, Papua New The closely related M. kermadecensis Guinea, elsewhere across small (the Kermadec pōhutukawa) has islands of the Pacific, and with one recently naturalised on Maui on the outlier species native to South Africa. Hawaiian Islands, and is considered a pest species. Both New Zealand New Zealand has 12 endemic Metrosideros species are species, and Metrosideros excelsa cultivated on Norfolk Island, where (pōhutukawa) is the most widely M. kermadecensis has naturalised cultivated with more than 30 and M. excelsa may be starting to named cultivars. In New Zealand, naturalise. pōhutukawa is cultivated successfully in mild locations often near the (small- sea (Fig. 21A–B), and as far south leaved pohuehue, wire ) as Stewart Island. Some of these Muehlenbeckia is a genus of locations, such as coastal Wellington, about 23 species belonging to the C are well outside of its natural range family. They are and pōhutukawa occupies habitats native to the southern hemisphere, Fig. 20 Leptospermum scoparium (mānuka). A, plant growing in pasture showing flowering that M. robusta would have when especially , Papua New at an early age. B, close-up of flowers. more widespread. These remnant Guinea, Australia and New Zealand. C, close-up of seed capsules. M. robusta populations may Photos: Trevor James.

18 New Zealand Garden Journal, 2014, Vol. 17(1) New Zealand has two endemic In some parts of New Zealand (e.g., species (M. astonii and urban Auckland, Wellington and along M. ephedroides) and three indigenous stretches of the Kaikoura coast) there (non-endemic) spp. (M. australis, are hybrid swarms between Australian M. axillaris and M. complexa). (M. insulare) and New Zealand (M. laetum) ngaio. Both species Both M. australis (large-leaved have been cultivated as fast growing muehlenbeckia, pōhuehue) and hedges or windbreaks, as they M. complexa (small-leaved pohuehue, withstand coastal winds, salt spray wire vine) are highly variable, with and drought. The leaves and fruits tangled, much branched growth A of both species (and others in the habits and dioecious flowers. In some genus) contain a liver toxin Ngaione situations, both can be considered which is poisonous to livestock. weeds in New Zealand. is a prostrate or climbing plant native to New Zealand where it is widespread throughout. It’s found in sunny habitats with climbing support, such as forest edges, cliff faces, scrub and B regenerating vegetation. M. australis can form dense mats over the tops of shrubs and smaller trees, sometimes smothering and breaking them. It is A also native to Norfolk Island where it is an endangered species. Muehlenbeckia complexa (Fig. 22A– E) is native to New Zealand and Lord Howe Island. It is found naturally throughout New Zealand as tangled C mats growing over sand dunes, rocks and coastal and lowland scrub. Wire vine has naturalised in Western Australia and possibly also escaped from cultivation in Canberra. Similarly, it is cultivated as an ornamental plant in California (and other States) and occasionally escapes from cultivation. It is considered invasive at the Golden Gate National Recreation Area, San D Francisco. laetum (ngaio) There are about 32 species of Myoporum in the B (formerly the genus was placed in its own family, the Myoporaceae). They are evergreen shrubs to small trees, with glabrous (hairless) vegetative parts and leaves often dotted with glands. Flowers are bell-shaped and E the fruit is a berrylike succulent drupe, Muehlenbeckia complexa (wire generally white to purple coloured, Fig. 22 vine). A, foliage and tangled stems. Photo: and often spread by birds. Species Phil Bendle. B, close-up of leaves. Photo: are naturally found in New Zealand, Phil Bendle. C, close-up of male flowers. C Australia, Pacific islands including Photo: Phil Bendle. D, close-up of female Fig. 23 Myoporum laetum (ngaio). Hawai‘i, Mauritius and China. flowers. Photo: Trevor James.E , close-up of fruit showing dark, three-grooved nuts held in A, mature tree growing at Pigeon Bay, New Zealand has four indigenous a fleshy cup. Photo: Trevor James. Banks Peninsula, Canterbury. Photo: Murray Dawson. , close-up showing leaf dotted species – the widespread B Australian ngaio (also called with glands. From Victory Beach, Otago endemic Myoporum laetum, the boobialla), Myoporum insulare, is fully Peninsula. Photo: Murray Dawson. C, flower Kermadec ngaio M. rapense subsp. naturalised in New Zealand, where and fruit. Photo: Phil Bendle. kermadecense, the recently described it is an environmental weed and a M. semotum of the Chatham Islands, National Pest Plant Accord plant. and M. obscurum, indigenous to Raoul Island and Australia.

New Zealand Garden Journal, 2014, Vol. 17(1) 19 New Zealand ngaio (Fig. 23A–C) In the 19th century and up the On Tristan da Cunha, 2430 kilometres has been introduced to several mid-20th century, harakeke was south of St Helena and also in countries including Spain, Portugal, the basis of a large fibre industry in the middle of the South Atlantic, Chile and the United States. It has New Zealand, providing rope, fabric, harakeke was traditionally used for become a serious invasive weed in matting and other fibre products. roof thatching where other materials coastal southern California and part During that time it was planted on were in short supply. Thatching was of Mexico’s Baja California peninsula, islands such as St Helena and Tristan typical until 1961 but continued to forming dense thickets that out- da Cunha in the South Atlantic, and some degree until the late 1980s compete native plants. It is on the the Isle of Man in the Irish Sea with before being fully replaced by zinc California noxious weeds list as ‘a an aim to establish similar industries roofs. On 19th December 2012, the most invasive wildland pest plant’ and there. island opened the Tristan Traditional there are programmes for its control. Thatched House Museum using On St Helena, the economy of the Myoporum laetum is also invasive harakeke once again as roof thatch island became heavily dependent on Robinson Crusoe Island (formerly (Fig. 26A–C) and following the on harakeke fibre (Fig. 24) until the Isla Más a Tierra, the second largest traditional quarried stone construction industry collapsed in the 1960s, island of the Juan Fernández Islands techniques for the walls of the when harakeke fibre could no longer off the coast of Chile). building. Harakeke is also considered compete with the new synthetic an invasive weed on the island. Phormium tenax (New Zealand flax, fibres. The last flax mill closed on harakeke) St Helena in 19667 but harakeke Like Cordyline, Phormium has continued to grow wild (it was first also been assigned to a range recorded as naturalising by 1852) and of monocotyledonous plant became extremely widespread and families, including the Agavaceae troublesome (Fig. 25), damaging the (Agavoideae), their own family the island’s ecosystem, and threatening Phormiaceae, the Hemerocallidaceae a unique flora of 43–49 endemic and most recently, the species of flowering plants and 13–16 Xanthorrhoeaceae. endemic ferns. A Phormium is a remarkable genus of only two species, P. cookianum (mountain flax, wharariki) andP. tenax (New Zealand flax, harakeke). Both subspecies of P. cookianum (subsp. cookianum and subsp. hookeri) are endemic to New Zealand. Phormium tenax (harakeke) has often been considered indigenous to both New Zealand and Norfolk B Island because it was abundant Fig. 24 Prisoners using a sisal hemp when discovered on Norfolk Island raspador on St Helena Island, 1911. After by Cook’s expedition in 17745. the closing down of the sugar mill in 1899 use was then made of the area for turning However, its historical absence from the raw flax into long soft fibres ready adjacent Phillip Island, the lack of for weaving into rope. Photo: Wikimedia fossilised Phormium pollen grains on Commons. Norfolk Island6, and the knowledge that Polynesians had visited before the British provides evidence that harakeke may have instead been introduced to Norfolk Island by earlier C Polynesian settlers (Coyne, 2009). Fig. 26 Phormium tenax (harakeke) Harakeke has long been used by used to construct the traditional Tristan Māori for textiles, cordage and Thatched House. A, cutting the flax ready for thatching, 29 October 2012. B, thatching day, nets. There are probably around 50 7 November 2012. C, a team photograph distinctive named weaving varieties, outside the newly thatched house, and more than 220 cultivars selected, 7 November 2012. Photos courtesy Tourism Department Tristan da Cunha. with green, yellow, red, purple and Fig. 25 Phormium tenax (harakeke) variegated leaves on plants of various growing as dense weeds near Diana’s Peak, Elsewhere in the world, harakeke stature. The ornamental cultivars are St Helena Island. Photo: Michelle Heyes, has also naturalised in Australia grown in many countries around the www.kevinandmichelle.co.uk. (Tasmania, south-eastern South world. Australia, eastern New South Wales,

5 William Wales, the ship’s astronomer, wrote: “Near the shore the ground is covered so thick with the New Zealand Flax Plant that it is scarce possible to get through it.” The potential value of harakeke was directly responsible for the island’s inclusion as an auxiliary settlement in the British Government’s plan for the colonisation of New South Wales; Norfolk Island was colonised in March 1788. 6 Although Phormium pollen grains are often underrepresented and hence difficult to detect in peat samples. 7 There is an excellent account of the history of flax milling on St Helena at http://jcgrimshaw.blogspot.co.nz/2011/06/flax.html.

20 New Zealand Garden Journal, 2014, Vol. 17(1) and possibly southern Victoria), considered to be ‘weeds in cultivation’ on Robinson Crusoe Island (Juan Hawai‘i (Big Island, Kaua‘i Island and but they may now have also escaped Fernández Islands) where it has also Moloka‘i Island), Robinson Crusoe into the wild. escaped from cultivation. Island (Juan Fernández Islands), and probably elsewhere such as Chile, Spain and South Africa. As a weed, harakeke grows into dense clumps that crowd out native vegetation. A single flower stalk can produce up to 10,000 seeds which are winged and dispersed by wind. (karo), P. eugenioides (lemonwood, tarata) and P. tenuifolium (black matipo, kōhūhū) Pittosporum is a genus of about 200 species of trees and evergreen shrubs in the family. Their natural range extends from New Zealand, Australia, Oceania, A A eastern Asia and some parts of Africa. New Zealand has 23 endemic species and one fully naturalised species, (sweet pittosporum, also called Australian cheesewood and Victorian box). Sweet pittosporum, originally endemic to moist areas on the Australian east coast has extended its natural range B in southern Australia and has become naturalised on Lord Howe Island and Norfolk Island. It is also one of the B most invasive species of this genus in other countries, and has widely naturalised in New Zealand, Guam, India, China, South Africa, St Helena, southern Europe (France, Spain and Portugal), Hawai‘i, California, Mexico, the Caribbean, South America C (Columbia, Bolivia, Chile, southern Fig. 27 Pittosporum crassifolium (karo). Brazil) and elsewhere. A, tree. B, red flowers.C , close-up of woody fruit capsule. Photos: Phil Bendle. are popular garden In New Zealand, karo is considered subjects for their low maintenance endemic to the upper half of the and glossy evergreen foliage. C North Island (East Cape and north There are more than 60 named Fig. 28 from about White Cliffs to Te Paki, (lemonwood). , tree. , flower-head cultivars derived mainly from A B and Three Kings and Great Barrier showing yellow flowers, a colour unusual three New Zealand endemic Island). However, plantings and in other species of Pittosporum. C, old fruit species: Pittosporum crassifolium, capsules. Photos: David Glenny. extensive bird dispersal of the seed P. eugenioides and P. tenuifolium. has extended the distribution of karo (kōhūhū; Although not as troublesome widely throughout New Zealand Fig. 29A–C) is the third New Zealand as P. undulatum, these three including the South, Stewart, and endemic pittosporum to have become New Zealand species have Chatham Islands. weedy abroad. Like the others, occasionally escaped cultivation in kōhūhū has also naturalised in other countries to become weedy. Pittosporum eugenioides temperate south-eastern Australia (lemonwood; Fig. 28A–C), has Pittosporum crassifolium (karo; (southern Victoria and sub-coastal occasionally naturalised in south- Fig. 27A–C) has naturalised in districts of central New South Wales) eastern Australia, where it is south-eastern Australia (southern and possibly also Tasmania. It is also regarded as an environmental weed Victoria and the coastal districts of said to have naturalised in California in Victoria and a minor or potential central New South Wales), Norfolk and Robinson Crusoe Island. environmental weed in New South Island, Hawai‘i and the Isles of Scilly Wales. Lemonwood is invasive in Britain. In California plants were

New Zealand Garden Journal, 2014, Vol. 17(1) 21 Solanum aviculare is indigenous eastern Europe and Russia and to New Zealand (where it is called have probably naturalised in these pōroporo), eastern Australia countries as well. (commonly known there as kangaroo Solanum laciniatum (Fig. 30A–C) is apple), Lord Howe Island, Norfolk closely related to S. aviculare with Island (where it is possibly extinct), which it shares the common name and also the West Papua Province of pōroporo in New Zealand. It too is Indonesia and Papua New Guinea. indigenous to Australia (and called the In some parts of southern Australia, large kangaroo apple, among other this species has naturalised beyond common names), where it naturally its natural range, on both western occurs in south-eastern Australia and eastern coastal areas. In and Tasmania. It has extended its New Zealand, the natural range of natural range in both Australia and S. aviculare includes Kermadec, New Zealand. In New Zealand it North, South and Chatham Islands. occurs naturally in the North, South, In the South Island, it occurs south to Stewart and Chatham Islands and is A about Banks Peninsula and Westland. also a common urban weed. It is sometimes an urban weed in Tetragonia tetragonioides New Zealand. (kōkihi, New Zealand spinach)

B A

B C Fig. 29 Pittosporum tenuifolium (kōhūhū). A, tree. B, dark red flowers.C , fruit capsules. Photos: Phil Bendle. A Solanum aviculare and S. laciniatum (pōroporo) Solanum (of its namesake family Solanaceae) is a diverse genus of C trees, shrubs and herbs that include Fig. 30 Solanum laciniatum (poroporo). crop plants such as tomatoes A, plant in flower. Photo: Phil Bendle. B, flowers. Photo: Murray Dawson. (previously species of Lycopersicon) C, mature fruit. Photo: Phil Bendle. and potatoes, as well as ornamental B plants cultivated for their flowers and Solanum aviculare (or possibly fruit, and weeds such as nightshades. S. laciniatum as the distinction Current estimates consider the between these two are not always number of Solanum species to be clear in overseas references) has also between 1500 and 2000. naturalised in New Caledonia, Hawai‘i (Lana‘i), in western USA (California New Zealand has three indigenous and Oregon) and probably elsewhere. species (the closely related pōroporos, S. aviculare and The leaves and unripe fruit of both S. laciniatum, and the small flowered S. aviculare and S. laciniatum contain the toxic alkaloid solasodine which nightshade S. nodiflorum; none C of which are endemic), as well as can be extracted and used as a precursor for producing contraceptive 27 exotic species (of which 20 are Fig. 31 Tetragonia tetragonioides fully naturalised and 7 are casual pills and other steroidal compounds. (New Zealand spinach). A, plant. B, leaves escapes). Both species are commercially and flowers.C , close-up of flower. cultivated for this purpose in China, Photos: Trevor James.

22 New Zealand Garden Journal, 2014, Vol. 17(1) Tetragonia is a genus of about 57 excelsa (pōhutukawa), Myoporum kevinandmichelle.co.uk), Naturally species in the family Aizoaceae, laetum (ngaio), and several native Native NZ Plants Ltd, Phil Bendle, native to temperate and subtropical pittosporums, are endemic and Trevor James (AgResearch) and regions mostly of the southern originally found nowhere else before ‘Wojsyl’ (via Wikimedia Commons). hemisphere (New Zealand, Australia, they became weedy in other areas. References southern Africa and South America). Others are indigenous to Bieleski, R. (2009). New Zealand’s New Zealand has two species, New Zealand and at least one other own weeds. Auckland Garden, Tetragonia implexicoma and country (and typically including December 2009. T. tetragonoides, both indigenous and Australia), such as Acaena novae- Coyne, P. (2009). Phormium tenax non-endemic. zelandiae (red bidibid), Cotula (New Zealand flax) – Norfolk australis (soldier’s button) and Island native? Cunninghamia Of all Tetragonia species, the best C. coronopifolia (bachelor’s button), 11(2): 167–170. known is T. tetragonioides (Fig. 31A– Dichondra repens (Mercury Bay Derraik, J. (2008). New Zealand C) which is used as a leafy food crop. weed), Leptospermum scoparium manuka (Leptospermum Among other common names, it is (mānuka), Solanum aviculare scoparium; Myrtaceae): a brief known as New Zealand spinach, and S. laciniatum (pōroporos) account of its natural history and but this belies the fact that it is also and Tetragonia tetragonioides human perceptions. New Zealand indigenous to Australia, Japan, Chile Garden Journal 11(2): 4–7. (New Zealand spinach). This and Argentina. Available at www.rnzih.org.nz/ means that for some, their weedy RNZIH_Journal/Pages_4-8_ It has become naturalised in many distributions may not necessarily from_2008_Vol11_No2.pdf. parts of the world. For example, in have been a result of spread from Di Tomaso, J.M. and Healy, E.A. the USA, it is weedy in many States New Zealand. (2007). Weeds of California and (including California, Connecticut, Excluded from this article are other Western States, Volume 1 & Florida, Georgia, Massachusetts, weedy species that are indigenous 2. University of California. North Carolina, North Dakota, to numerous countries including Green, M.; Ellis, J.; Schwarz, A.; New York, Ohio, Pennsylvania, New Zealand. Some can have Green, N.; Lind, D.; Bluck, B. Washington, Wisconsin, West southern hemisphere distributions, (2003). For and against mangrove Virginia), the Hawaiian Islands and such as Pteridium esculentum control. NIWA Information Series Porto Rico. (bracken), and others have near- No. 31. Available at www.niwa. Summary cosmopolitan distributions as co.nz/sites/niwa.co.nz/files/ This article provides a comprehensive exemplified by the likes of jersey import/attachments/mangrove. pdf. survey of native New Zealand plants cudweed, Pseudognaphalium from a diverse range of families – luteoalbum (also known as Harris, G. (1998). Invasive namely the Acanthaceae, Aizoaceae, Helichrysum luteoalbum and several New Zealand weeds: our native plant invaders. CalEPPC News: Araliaceae, Asparagaceae, synonyms). Jersey cudweed is so A quarterly publication of the Asteraceae, Convolvulaceae, widely distributed that it is unclear California Exotic Pest Plant Corynocarpaceae, Crassulaceae, where it is native and where it is Council 6(4): 8–9. Available at Cyperaceae, Malvaceae, Myrtaceae, naturalised. www.cal-ipc.org/resources/news/ Onagraceae, Pittosporaceae, Final comments pdf/caleppc_news878.pdf. Poaceae, Polygonaceae, Rosaceae, Many of the New Zealand native Harris, G. (2002). Our native plant Rubiaceae, Sapindaceae, plants mentioned in this article invaders. The New Zealand Scrophulariaceae, Solanaceae and have been traditionally, culturally, Garden Journal (Journal of the the Xanthorrhoeaceae – that have aesthetically, horticulturally and at Royal New Zealand Institute of become weedy in other regions of the times economically important – the Horticulture) 5(1): 6–8. Available world. very reasons why they were first at www.rnzih.org.nz/pages/ Not surprisingly, these regions – such cultivated and distributed so widely. NativeWeeds.htm and www. rnzih.org.nz/RNZIH_Journal/ as in southern Australia, Tasmania, People continue to enjoy these Pages6-8_from_2002_Vol5_No1. mild regions of the UK and the USA positive qualities in environments pdf. including especially California, and where the plants are not out of place Howell, C. (2008). Consolidated oceanic islands such as Hawai‘i and and troublesome. After all, one list of environmental weeds in the Juan Fernández Islands – have person’s weed is another’s treasure! New Zealand. DOC Research & similar climates or conditions to the Acknowledgements Development Series 292. native New Zealand habitats where My thanks to those who kindly Linder, H.P.; Baeza, M.; Barker, the plant species are originally from. provided images for this article N.P.; Galley, C.; Humphreys, Some New Zealand species, such additional to my own: David Glenny A.M.; Lloyd, K.M.; Orlovich, as Austroderia richardii (toetoe), (Landcare Research), Dawn D.A.; Pirie, M.D.; Simon, B.K.; Coprosma repens (taupata) and Repetto (Tourism Department Walsh, N.; Verboom, G.A. (2010). C. robusta (karamū), Cordyline Tristan da Cunha, on behalf of the A generic classification of the australis (cabbage tree), Epilobium original photographers), Leon Perry (Poaceae). brunnescens and E. nummulariifolium (Museum of New Zealand Te Papa Annals of the Missouri Botanical Garden 97: 306–364. (creeping willow-herbs), Metrosideros Tongarewa), Michelle Heyes (www.

New Zealand Garden Journal, 2014, Vol. 17(1) 23 Mabberley, D.J. (2008). Mabberley’s Starr, F.; Starr, K.; Loope, L. (2004). New Zealand Plant Conservation plant book, a portable dictionary New plant records from the Network: www.nzpcn.org.nz. of plants, their classification and Hawaiian Archipelago. In: New Zealand Species Overseas: uses. 3rd edition. Cambridge Evenhuis, N.L. and Eldredge, Te Ara Encyclopedia of University Press. L.G. (eds). Records of the New Zealand: www.teara.govt. Metcalf, L.J. (1987). The cultivation of Hawaii Biological Survey for nz/en/new-zealand-species- New Zealand trees and shrubs. 2003. Part 2: Notes. Bishop overseas/page-1. Reed Methuen Publishers Ltd, Museum Occasional Papers 79: Plant Threats to Pacific Ecosystems: Auckland. 20–30. Available at http://hbs. index to PIER lists: www.hear.org/ Motooka, P. et al. (2003). Weeds of bishopmuseum.org/pdf/op79.pdf. pier/threats.htm. Hawai‘i’s pastures and natural Websites (accessed June 2014) Seeds of hopelessness: areas: an identification and Building the Tristan Thatched Opinion: Wanganui Chronicle management guide. College of House – a new live museum News: www.nzherald. Tropical Agriculture and Human built using traditional materials co.nz/wanganui-chronicle/ Resources, University of Hawai‘i and methods by Tristan opinion/news/article.cfm?c_ at Mānoa. Available at www.ctahr. Islanders: www.tristandc.com/ id=1503423&objectid=11133036. hawaii.edu/invweed/weedsHi.html thatchedhousebuilding.php. Saint Helena 15.55 South 5.43 West: MPI Biosecurity New Zealand (2012). Environmental Weeds of Australia Flax: http://jcgrimshaw.blogspot. National Pest Plant Accord. Lucid Mobile app: https:// co.nz/2011/06/flax.html. Ministry of Primary Industries play.google.com/store/apps/ T.E.R:R.A.I.N – Taranaki Educational Biosecurity New Zealand, details?id=org.lucidcentral.mobile. Resource: Research, Analysis Wellington. ewa. and Information Network: Popay, I.; Champion, P.; James, T. Flora of New Zealand: www.terrain.net.nz/terrain/home. (2010). An illustrated guide to www.nzflora.info. html. common weeds of New Zealand. GB Non-natives Factsheet Editor: Te Motu Kairangi – Miramar Third Edition. New Zealand Plant Acaena novae-zelandiae: www. Ecological Restoration: Weed Protection Society (Inc). brc.ac.uk/gbnn_admin/index. Management: Bad and fake Smith, C.W. (1985). Impact of php?q=node/290. natives: www.temotukairangi. alien plants on Hawai‘i’s native co.nz/fakenatives.php. Global Compendium of Weeds: biota. In: Stone, C.P. and Scott, www.hear.org/gcw. Te Papa’s Blog: New Zealand plants J.M. (eds). Hawai‘i’s terrestrial abroad part 2: the troublemakers: Hawaii’s Most Invasive Horticultural ecosystems: preservation and http://blog.tepapa.govt. Plants: List of species to Management. Cooperative nz/2013/07/05/new-zealand- avoid planting: www.hear.org/ National Park Resources Studies plants-abroad-part-2-the- hortweeds. Unit, University of Hawaii, Mānoa. troublemakers/ Massey University Weeds Database: Starr, F.; Starr, K.; Loope, L. (2003). USDA PLANTS Database: Hydrocotyle: www.massey.ac.nz/ Leptospermum spp. Tea tree. http://plants.usda.gov. massey/learning/colleges/college- Myrtaceae. Available at www. Weeds of Australia identification hear.org/starr/hiplants/reports/pdf/ of-sciences/clinics-and-services/ weeds-database/hydrocotyle.cfm. tool: www.business.qld.gov. leptospermum_spp.pdf. au/industry/agriculture/land- National Pest Plant Accord: MPI management/health-pests- Biosecurity New Zealand: weeds-diseases/weeds-and- www.biosecurity.govt.nz/nppa. diseases/weed-identification-tool. New Zealand Christmas tree: Wikipedia: http://en.wikipedia.org/ Metrosideros excelsa: Invasive wiki/Main_Page. species South Africa: www.invasives.org.za/invasive- species/item/281-new-zealand- christmas-tree|metrosideros- excelsa.html.

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