Leptospermum scoparium
(manuka)

Pictures

Picture	Title	Caption	Copyright
Title Habit Caption Manuka (Leptospermum scoparium) bush in reverting grassland Copyright ©Trevor James/Hamilton, New Zealand	Habit	Manuka (Leptospermum scoparium) bush in reverting grassland	©Trevor James/Hamilton, New Zealand
Title Flowers Caption Manuka (Leptospermum scoparium), flowers Copyright ©Trevor James/Hamilton, New Zealand	Flowers	Manuka (Leptospermum scoparium), flowers	©Trevor James/Hamilton, New Zealand
Title Flowers Caption Manuka (Leptospermum scoparium), close-up of flowers Copyright ©Trevor James/Hamilton, New Zealand	Flowers	Manuka (Leptospermum scoparium), close-up of flowers	©Trevor James/Hamilton, New Zealand
Title Fruits Caption Manuka (Leptospermum scoparium), seed capsules Copyright ©Trevor James/Hamilton, New Zealand	Fruits	Manuka (Leptospermum scoparium), seed capsules	©Trevor James/Hamilton, New Zealand
Title Fruits Caption Manuka (Leptospermum scoparium), close-up of seed capsules Copyright ©Trevor James/Hamilton, New Zealand	Fruits	Manuka (Leptospermum scoparium), close-up of seed capsules	©Trevor James/Hamilton, New Zealand

Identity

Preferred Scientific Name

• Leptospermum scoparium J. R. Forst. & G. Forst.

Preferred Common Name

• manuka

Other Scientific Names

• Leptospermum floribundum
• Leptospermum scoparium var. eximum B.L. Burtt (1940)
• Leptospermum scoparium var. forsteri S. Schauer (1841)
• Leptospermum scoparium var. incanum Cockayne (1917)
• Leptospermum scoparium var. linifolium (Sol. ex Aiton) R.Br. ex Aiton (1811)
• Leptospermum scoparium var. martinii hort.
• Leptospermum scoparium var. myrtifolium (Sol. ex Aiton) R.Br. ex Aiton (1811)
• Leptospermum scoparium var. nichollii Turrill (1912)
• Leptospermum scoparium var. nichollsii Dorr. Sm.
• Leptospermum scoparium var. parvum Kirk (1899)
• Leptospermum scoparium var. prostratum Kirk (1899)
• Leptospermum scoparium var. rotundifolium Maiden & Betche
• Leptospermum scoparium var. scoparium J.R. Forst. & G. Forst. (1776)

International Common Names

• English: broom tea; manuka; manuka (Australia); tea tree
• French: leptosperme à balais

Local Common Names

• : Australian tea tree; New Zealand tea bush; New Zealand tea tree; red tea tree
• Australia: broom tea tree
• Brazil: árvore-chá; érica; falsa-érica; leptospermo
• Germany: Manukastrauch, Roter; Südsee-Myrte, Besenartige
• New Zealand: kahikatoa; katoa; manuka; pata; rauiri; rauwiri; tea tree
• South Africa: manuka myrtle; manukamirt
• Sweden: rosenmyrten
• UK/England and Wales: tea tree
• USA: broom tea tree

EPPO code

• LEKSC (Leptospermum scoparium)

Summary of Invasiveness

Leptospermum scoparium, commonly known as manuka, is a shrub or small tree native to New Zealand and Australia. It is an early successional species of disturbed areas in forests in New Zealand and its seeds are light, wind-dispersed and numerous. Seeds germinate in bare patches, and the plant grows quickly, establishing dominance over low-growing vegetation. Plants die out after about 60 years, being replaced by larger, longer living trees. However, in impoverished or wet soils, manuka can become the dominant climax vegetation. Manuka has been seen by generations of New Zealand’s hill country farmers as a serious problem in newly cleared and oversown grassland.

Manuka is grown as an ornamental garden plant in many countries, with cultivars widely available. In South Africa, the species is listed as ‘under surveillance’ in the Conservation of Agricultural Resources Act 1983. It is also considered a possible threat in Hawaii, where it seems to spread more quickly than the related Leptospermum laevigatum (Starr et al., 2003). In Britain, where it has been cultivated in gardens since 1772 (Dawson, 2009), it has been only recorded as naturalised at Tresco Abbey in the Scilly Isles, although unreported naturalisation may have occurred elsewhere (Stephens et al., 2005)

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Myrtales
•                         Family: Myrtaceae
•                             Genus: Leptospermum
•                                 Species: Leptospermum scoparium

Notes on Taxonomy and Nomenclature

Stephens et al. (2005) reported the following on this species taxonomy: 

“A comprehensive taxonomic revision of the genus Leptospermum listed 79 species (Thompson, 1989), which has been increased to 83 with later additions (Dawson, 1997). L. scoparium is one of 13 species included in the Leptospermum myrtifolium subgroup, the defining characteristics of which are deciduous sepals and persistent strongly wooded fruit-valves (Thompson, 1989). The Australian species within this sub-group are extremely difficult to define; L. continentale and L. rotundifolium were recently elevated by Thompson (1989) from L. scoparium varieties to species rank. The species L. juniperinum and L. squarrosum have both been recorded as varieties of L. scoparium (Thompson, 1989), and the endemic Tasmanian L. scoparium var. eximium could be considered to warrant species status, displaying lignotuber development which is not found in New Zealand’s L. scoparium (Bond et al., 2004).”

Dawson (2009) discussed the many forms found in cultivation including red-flowered, pink-flowered, double-flowered, prostrate and dwarf forms, and concluded that the pool of variation for L. scoparium is by no means exhausted.

Description

Webb et al. (1988) describe L. scoparium as the following:

“Shrub of diverse habit, or tree up to c. 4 m high. Bark shedding in long strips. Branchlets and young leaves clothed in silky hairs. Leaves subsessile, ± 4-12-(20) × 1-4 mm, of 2 main forms on different plants, narrow-lanceolate or ovate, coriaceous, rigid, acute, pungent, erect to patent. Flowers axillary, or occasionally terminal on branchlets, ± sessile, usually solitary. Hypanthium broadly turbinate; calyx lobes ± triangular, caducous. Petals c. 6 mm long, ± suborbicular, usually white, rarely pink, patent. Stamens c. 20, < to slightly > style; filaments much more slender than style. Ovary apex glabrous. Capsule 5-celled, 3-7 × 4-10 mm, woody, long-persistent, distinctly exserted beyond receptacle rim”.  

Plant Type

Distribution

Manuka is native to New Zealand and Australia but has been introduced and cultivated in a number of countries, including the United States, Britain, South Africa and Madeira (Starr et al., 2003; DAISIE, 2008; Dawson, 2009). In Australia, it is generally found in coastal areas in Tasmania and Victoria and has a broad range within New South Wales (Atlas of Living Australia, 2012; Thompson and Logan, 2012). The species is also widespread in its native origin in New Zealand (Webb et al., 1988). The species establishment in Hawaii threatens other biodiversity and so it is now recognised as an invasive species.  

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

Although native to New Zealand, Stephens et al. (2005) suggest that manuka spread extensively within the country only after the opening up of newly disturbed areas as a result of human settlement. In Hawaii, according to Starr et al. (2003), manuka and other species of Leptospermum were planted for forestry, slope stabilisation or landscaping and later naturalised and spread, sometimes forming dense stands. Manuka has also been planted as an ornamental in South Africa, and is proposed as a declared plant, but more information is required before it can be listed (SABONET, 2002).

Introductions

Risk of Introduction

L. scoparium has been planted as an ornamental in several countries, including the United States, Britain and South Africa (USDA- ARS, 2012), but has only naturalised and become invasive in Hawaii and possibly South Africa. It is however, identified as a high risk weed for the Pacific Islands with a Weed Risk Assessment Score of 20 (PIER, 2012).

Habitat

In New Zealand, Webb et al. (1988) describe its habitat as “Lowland to subalpine areas in various habitats, especially open slopes, river banks, forest margins, and scrub, where it often forms the dominant vegetation.”

Habitat List

Hosts/Species Affected

L. scoparium may negatively affect pasture species, and the shrub has been particularly problematic for hill country farmers in New Zealand.

Growth Stages

Biology and Ecology

Genetics

Stephens et al. (2005) reported that throughout New Zealand, L. scoparium is normally diploid with 22 chromosomes (Dawson 1987, 1990), but two triploid and one tetraploid cultivars have been described (Dawson, 1990) and wild aneuploids have been recorded.

Reproductive Biology

According to Primack and Lloyd (1980), L. scoparium is an andromonoecious species; although, the variation in the percentage of perfect flowers is mainly related to the environment. Overall control of flowering is determined by temperature and day-length. L. scoparium flowering is initially activated by a long-day flowering cue, although bud development is restrained by cool temperatures throughout winter leading to spring flowering when the temperature restraint is lifted (Zieslin and Gottesman, 1986). Bennik (2009) found that the species is partly self-compatible but relies more heavily on cross pollination for higher yields of capsule and seed set.

Pollination of L. scoparium is by a range of insects – large tachinid and calliphorid flies, small Diptera, Hymenoptera, moths, craneflies and honeybees (Stephens, 2005).

Physiology and Phenology

Fruit capsules (of which 8000 have been recorded on a 10 year old plant) each contain 240 to 470 seeds with an average of about 300, each seed weighing about 0.005 mg (Grant, 1967). Seed falls throughout the year, with a major peak in late winter-spring and a smaller peak in autumn. Seed viability was estimated by Grant (1967) at 19.05% and germination percentage was similar. Light is required for successful germination, which can occur at temperatures of between 4.5^oC and 32^oC. In the field, Grant (1967) found that most seedlings appeared in pasture in the spring (September-October).

Associations

L. scoparium is found in many different environments and is therefore associated with a wide range of different species, ranging from scrubland associations on low fertility hill country with gorse (Ulex europaeus) and broom (Cytisus scoparius) to the early stages of succession to larger native trees and shrubs. L. scoparium also has direct associations with different species of native mistletoes (Viscum spp.) (Stephens et al. 2005).

Environmental Requirements

L. scoparium occupies a variety of environments in New Zealand, either as an early succession species in the development of forest or as the permanent dominant species on sites that are too wet, dry, cold, exposed, infertile or unstable for the establishment of climax forest (Stephens, 2005). This indicates that the species is extremely wide-ranging in its environmental requirements.

Climate

Latitude/Altitude Ranges

Soil Tolerances

Soil drainage

• free
• impeded
• seasonally waterlogged

Soil reaction

• acid
• very acid

Soil texture

• heavy
• light
• medium

Natural enemies

Notes on Natural Enemies

The insect species most commonly found affecting L. scoparium in New Zealand are the introduced scale insects Eriococcus orariensis and E. leptospermi and the scale insect Coelostomidia wairoensis, which is endemic to New Zealand. Manuka blight, caused by the introduction to New Zealand and subsequent deliberate spread of E. orariensis rapidly eradicated large areas of manuka (Hoy, 1961). However the later spread of the entomogenous fungus Myriangium thwaitesii led to the recovery of manuka in many areas. The insects often also carry the spores of sooty moulds, one of which is Capnodium elegans, and these mould diseases may contribute to the effect of the insects.

Other insect enemies include manuka beetle (Pyronota spp.), manuka moth (Declana floccose), webworm (Heliostibes atychioides), the larvae of the longhorn beetle (Ochrocudus huttoni), the mite Aceria manukae and the wood borer Amasa truncates (Molloy, 1975; Brockerhoff and Bain, 2000).

Means of Movement and Dispersal

Natural Dispersal (Non-Biotic)

The species seeds prolifically and the seed is light and readily transported by wind. Release of seeds from the capsules is expedited by burning.

Accidental Introduction

This form of introduction is unlikely to occur.

Intentional Introduction

The species has been deliberately introduced and transported to other countries, primarily as an ornamental but also for forestry and soil conservation purposes.

Pathway Causes

Pathway Vectors

Plant Trade

Impact Summary

Economic Impact

In the past in New Zealand, hill country farmers (and to some extent governments) have spent much time and effort in controlling manuka, which tends to spring up in large numbers when land is cleared for pastoral agriculture. Besides the lost production from its direct effects on pasture, costs have included hand slashing, mechanised clearing and herbicides used in attempts to maintain pastures clear of manuka and other species like gorse (Ulex europaeus) and broom (Cytisus scoparius). However, because of the increasing economic value of manuka honey, large blocks of land in New Zealand are currently being planted in manuka. Consequently, this plant is no longer seen as a weed causing negative economic impacts in New Zealand but one that can be financially viable. Furthermore, research funding is now being directed towards growing profitable strains of the plant rather than limiting its growth (Harrington and Gregory, 2009; Massey University, 2012).  

Environmental Impact

L. scoparium plays an integral part in many of New Zealand’s natural ecosystems, and is now considered valuable for its role in succession and slope stabilisation.

In Hawaii, Starr et al. (2003) reported: “L. laevigatum and L. scoparium were both planted on Lana'i during forestry efforts in part to stabilize the eroding soils. According to Robert Hobdy (DLNRDOFAW) (pers. comm.), both species stayed put for a long time then suddenly began to spread, with L. scoparium being the more aggressive of the two. With thick shrubby growth, not much else can grow beneath Leptospermum infestations. Seeds are light and numerous, being spread on the wind.”

Impact on Habitats

Not relevant in New Zealand, and no information from elsewhere.

Impact on Biodiversity

Not relevant in New Zealand, and no specific information from elsewhere.

Social Impact

In the past, many hill country farmers have despaired at the lack of control of manuka.

Recently in New Zealand, disputes over the ownership of manuka honey produced from wild manuka have resulted in some bee-keepers sabotaging hives of opposition keepers in attempts to get the manuka honey for themselves (K.C. Harrington, Massey University, New Zealand, personal communication, 2013).     

Risk and Impact Factors

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Fast growing
• Has high reproductive potential
• Gregarious
• Has high genetic variability

• Ecosystem change/ habitat alteration
• Modification of successional patterns
• Monoculture formation
• Negatively impacts agriculture

• Competition - monopolizing resources
• Competition - shading
• Herbivory/grazing/browsing
• Rapid growth

• Highly likely to be transported internationally deliberately
• Difficult/costly to control

Uses

Economic Value

Firewood

New Zealand Maori used L. scoparium as firewood, among other uses, and it continues to be highly valued as firewood. A modern website says ‘Manuka firewood is a native hardwood and burns extremely hot and slow, making it the best available. Suitable for open fires, pizza ovens and log fires (Waikato Firewood Company, 2008).

Essential Oils

Stephens et al. (2005) reviewed the status of essential oils in New Zealand’s L. scoparium populations. These have received considerable attention in the past 20 years. Analysis of commercially available oils showed 100 components of which 51 were identified and made up about 95% of the content. Triketones, sesquiterpene hydrocarbons and monoterpene hydrocarbons are the three main components, and the proportions of these three groups vary considerably between populations in different parts of the country. Manuka oil is readily available from many different sources, and is touted as being useful for the complexion, for aromatherapy, as an antibiotic, and for many medical conditions, especially those affecting the skin.

Manuka Honey

L. scoparium is a major source of honey harvested by the introduced honeybee (Apis mellifera) and the production of manuka honey has become a major industry both in New Zealand and elsewhere. Although many honey types have antibacterial properties because of the presence of hydrogen peroxide, only manuka honey has a high level of non-peroxide anti-bacterial activity (Stephens et al. 2005). This non-peroxide antibacterial factor has been named Unique Manuka Factor (UMF). Manuka honey is now used in many medical products in many countries.

Amenity Plant

L. scoparium is used in amenity plantings along roadsides in New Zealand, and the many attractive cultivars are extensively used as garden ornamentals in many countries, including Britain, the United States, New Zealand, Australia and South Africa.

Social Benefit

According to Stephens et al. (2005), New Zealand Maori traditionally used L. scoparium for food, medicine and timber. A sugary gum sometimes found on the branches was given to infants or used to treat coughs in adults. Infusions of leaves or bark were used for various ailments, and the timber was used for implements. L. scoparium is named tea-tree because Captain James Cook used its leaves for brewing tea when he first arrived in New Zealand in 1769.

Environmental Services

The species germinates and grows quickly, making it ideal as a soil stabiliser. Under natural conditions in New Zealand, dense stands eventually thin and the species is replaced by taller-growing forest species. In Hawaii, L. scoparium was introduced partly for this reason, but is now regarded as invasive (Starr et al., 2003). However, Harris (2004) adds that “While they are classed as an "alien invasive pest plant" they have provided some benefits by stabilising ridge tops that have eroded following grazing by goats.”

Uses List

Environmental

• Amenity
• Erosion control or dune stabilization
• Land reclamation
• Landscape improvement
• Revegetation
• Soil conservation
• Wildlife habitat

Fuels

• Fuelwood

General

• Botanical garden/zoo
• Sociocultural value

Human food and beverage

• Honey/honey flora

Materials

• Essential oils

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical

Ornamental

• Potted plant

Detection and Inspection

The species is easily recognised by its distinctive and often colourful flowers.

Prevention and Control

Prevention   

Public awareness

In Hawaii, Starr et al. (2003) suggest that the public could be discouraged from planting Leptospermum species or other potentially invasive non-native plants.

Physical/Mechanical Control

L. scoparium was battled by generations of hill country farmers in New Zealand. They used fire, manual pulling or cutting (often by teams of workers brought in from Fiji and other Pacific islands), mechanical clearing with bulldozers and, since the Second World War, herbicides. Cutting or slashing works well on manuka, since plants do not regrow but new plants will continue to emerge from the cleared area from seed in the soil.  

Biological Control

In New Zealand, biological control was actively encouraged by farmers when scale insects appeared in the 1950s but the initial onslaught was later mitigated by the appearance of an entomogenous fungus which attacked the scale insects and led to the recovery of the manuka. 

In South Africa, the leaf-mining gracillariid moth, Parectopa thalassias, from Australia, and an unidentified gall-forming midge, Dasineura spp. have been released for the control of the related Leptospermum laevigatum (Starr et al., 2003).

L. scoparium is relatively unpalatable to livestock (Pande et al., 2002) although goats have been used to control manuka and other scrub weeds in hill country (Batten, 1990). 

Chemical Control

In New Zealand chemical control has been regularly used on L. scoparium since the herbicide 2,4,5-T was introduced in the late 1950s. Nowadays the herbicides most likely to be used are metsulfuron or glyphosate, although triclopyr amine, with or without picloram, is sometimes used. However, controlling existing plants of manuka rarely solves the problem because of germination of seeds already in the soil or blown in from nearby plants. Improved pasture competition (liming, fertiliser and improved pasture species) and controlled grazing must be combined with chemical control of existing plants if the manuka is to be effectively controlled.

However, farmers have been encouraged to consider the value and uses of existing manuka stands before spraying herbicides (Munro, 2006). Furthermore, scientists are now concentrating efforts on the use of herbicides to ensure good establishment of manuka for honey production rather than the use of herbicides for its' removal (K.C. Harrington, Massey University, New Zealand, personal communication, 2013).

Ecosystem Restoration

Not relevant, at least in New Zealand.

Gaps in Knowledge/Research Needs

Stephens (2005) pointed out the need for a thorough clarification of the species in New Zealand and Australia.

Apart from its reported invasiveness in Hawaii and possibly in South Africa, little information on its invasive nature is available, despite it having been planted in gardens, nurseries and botanical gardens in a range of areas for a number of years. More information on when it is likely to become invasive would also be useful.

References

Allan Herbarium, 2000. Nga Tipu o Aotearoa - New Zealand Plant Names Database. New Zealand: Landcare Research. http://nzflora.landcareresearch.co.nz/

Atlas of Living Australia, 2012. Atlas of Living Australia. Canberra ACT, Australia: GBIF. www.ala.org.au

Batten GJ, 1990. Hill country goat farming in perspective. Proceedings of the New Zealand Grassland Association, 51:61-64.

Bennik RM, 2009. The effects of honeybees (Apis mellifera) on the biodiversity of manuka (Leptospermum scoparium) patches. Palmerston North, New Zealand: Massey University, 134. http://mro.massey.nz/bitstream/handle/10179/1269/02whole

Bond WJ; Dickinson KJM; Mark AF, 2004. What limits the spread of fire-dependent vegetation? Evidence from geographic variation of serotiny in a New Zealand shrub. Global Ecology and Biogeography, 13(2):115-127.

Brockerhoff EG; Bain J, 2000. Biosecurity implications of exotic beetles attacking trees and shrubs in New Zealand. In: New Zealand Plant Protection Volume 53, 2000. Proceedings of a conference, Commodore Hotel, Christchurch, New Zealand, 8-10 August 2000 [ed. by Zydenbos, S. M.]. Rotorua, New Zealand: New Zealand Plant Protection Society, 321-327.

DAISIE, 2012. European Invasive Alien Species Gateway. European Invasive Alien Species Gateway. http://www.europe-aliens.org/

Dawson MI, 1987. Contributions to a chromosome atlas of the New Zealand flora - 29. Myrtaceae. New Zealand Journal of Botany, 25(3):367-369.

Dawson MI, 1990. Leptospermum scoparium (manuka) - chromosome variation of cultivars. Horticulture in New Zealand, 1(2):15-19.

Dawson MI, 2009. A history of Leptospermum scoparium in cultivation. New Zealand Garden Journal, 12:121-125.

Grant DA, 1967. Factors affecting the establishment of manuka (Leptospermum scoparium). Proceedings 20th N.Z. Weed Pest Control Conf. 129-34.

Harrington KC; Gregory SJ, 2009. Field assessment of herbicides to release native plants from weeds. New Zealand Plant Protection [Proceedings of the New Zealand Plant Protection Society's Annual Conference, Otago Museum Conference Centre, Dunedin, New Zealand, 11-13 August 2009.], 62:368-373. http://www.nzpps.org/journal/62/nzpp_623680.pdf

Harris G, 2004. Our native plant invaders. The New Zealand Garden Journal, 5:6-8. http://www.rnzih.nz/pages/NativeWeeds

Hoy JM, 1961. Ericoccus orariensis Hoy and other Coccoidea (Homoptera) associated with Leptospermum Forst. species in New Zealand. DSIR Bulletin, 141.

ITIS, 2013. Integrated Taxonomic Information System (ITIS). Washington, DC, USA: Smithsonian Institution/NMNH. http://www.itis.gov/

Massey University, 2012. News: Manuka honey research to grow industry. Palmerston North, New Zealand: Massey University. http://www.massey.nz/massey/about-massey/news/article

Molloy BPJ, 1975. Manuka and kanuka. New Zealand's Nature Heritage, 6:2469-2474.

Munro V, 2006. Coutry-Wide Northern, Special Report: New Option for steep, erosion-prone land. Feilding, New Zea: NZX Agri. http://www.country-wide.nz/article/4996

Pande RS; Kemp PD; Hodgson J, 2002. Preference of goats and sheep for browse species under field conditions. New Zealand Journal of Agricultural Research, 45(2):97-102.

PIER, 2012. Pacific Islands Ecosystems at Risk. Honolulu, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html

Primack RB; Lloyd D, 1980. Andromonoecy in the New Zealand montane shrub Leptospermum scoparium (Myrtaceae). American Journal of Botany, 67:361-368.

SABONET, 2002. Invasive alien plants in southern Africa., South Africa: SABONET (Southern African Botanical Diversity Network). http://www.sabonet.org.za/

Starr F; Starr K; Loope L, 2003. Leptospermum scoparium. Haleakala Field Station, Maui, USA: United States Geological Survey- Biological Research Division. http://www.hear.org/

Stephens JMC; Molan PC; Clarkson BD, 2005. A review of Leptospermum scoparium (Myrtaceae) in New Zealand. New Zealand Journal of Botany, 43(2):431-449. http://www.rsnz.org

Thompson J, 1989. A revision of the genus Leptospermum (Myrtaceae). Telopea, 3(3):301-449.

Thompson J; Logan V, 2012. Leptospermum scoparium. Sydney, Australia: The Plant Information Network System of The Royal Botanic Gardens and Domain Trust. http://plantnet.rbgsyd.au/cgi-bin/NSWfl

USDA-ARS, 2012. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

Wagner WL; Herbst DR; Sohmer SH, 1999. Manual of the flowering plants of Hawaii. Revised edition. Honolulu, Hawaii, USA: University of Hawaii Press/Bishop Museum Press, 1919 pp.

Waikato Firewood Company, 2008. Waikato Firewood. New Zealand. http://www.waikatofirewood.co.nz/

Webb CJ; Sykes WR; Garnock-Jones PJ, 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Christchurch, New Zealand: Botany Division, DSIR, 1365 pp.

Zieslin N; Gottesman V, 1986. Environmental factors involved in growth, flowering and post-harvest behaviour of flowers of Leptospermum scoparium J.R. & G.Forst. Israel Journal of Botany, 35(2):101-108.

Links to Websites

Organizations

New Zealand: LCR Landcare Research, PO Box 40, Lincoln 7640, http://www.landcareresearch.co.nz/home

New Zealand: New Zealand Plant Protection Society, NZPPS Secretary: Heather Pearson, Ministry for Primary Industries, Christchurch, http://www.nzpps.org/index.php

Contributors

27/10/12: Original text by:

Ian Popay, consultant, New Zealand, with the support of Landcare Research.

Distribution Maps