Leptospermum scoparium J.R.Forst. & G.Forst., Myrtaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 20 (Go to the risk assessment)

Other Latin names:  Kunzea scoparium

Common name(s): [more details]

English: broom teatree, manuka, New Zealand tea tree, tea tree

Habit:  tree

Description:  "Shrubs or small trees to 2-5 m tall, bark shredding into long strips; young branches silky pubescent.  Leaves linear-lanceolate to linear-elliptic or occasionally ovate, 9-14 mm long, 1.5-4 mm wide, silky pubescent when young, soon glabrate, gladular-dotted, apex attenuate to a pungent tip.  Sepals broadly deltate, ca. 1.5-3.5 mm long, minutely tuberculate, glabrous, apex obtuse; petals pink or white, ca. 5-8 mm long, glandular-dotted.  Capsules 5-valved, 5-6 mm in diameter, slightly exserted from hypanthium"  (Wagner et al., 1999; p. 963).

Habitat/ecology:  "This small, scrubby tree forms thickets which crowd out other plants. In Hawai‘i, it has infested goat-eroded ridgetops, resulting in their stabilization.  It appears to have allelopathic activity like many other members of the Myrtaceae.  In Hawai‘i, it is found in mesic habitats between 300-700 m elevation" (Smith, 1985; p. 193).  In Hawai‘i, "extensively cultivated and now naturalized, primarily in disturbed mesic to wet forest and areas of forestry plantings, 330-1,220 m" (Wagner et al., 1999; p. 963).

Propagation:  Prolific seed producer. Seeds are dispersed by wind.

Native range:  Australia and New Zealand.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Cook Islands Southern Cook Islands	Rarotonga Island		Sykes, Bill (year unknown) Recorded by Cheeseman on Raemaru peak and perhaps a remnant of cultivation per Bill Sykes.
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 963)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 963)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2004) (p. 14) East Maui. Voucher cited: Oppenheimer, S. Perlman, J. Lau & R. Aguraiuja H70206 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 963)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (pp. 162-163)
New Zealand New Zealand	New Zealand (country)	native	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 865) "Lowland to subalpine areas in various habitats, especially open slopes, river banks, forest margins, and scrub, where it often forms the dominant vegetation".

Comments:  Other members of this genus, including L. flavescens, L. laevigatum and L. polygalifolium, are also potentially invasive. See also listing for Kunzea ericoides.

Control: 

Physical: "DOFAW, Katie Cassel (Kōke‘e Museum), and U.S. Army all reported that decapitated New Zealand tea trees do not resprout"  (Motooka et al., 2003).

Chemical: Reported to be sensitive to triclopyr (Motooka et al., 2003).

Additional information:
Report (PDF format) from US Geological Survey, Biological Resources Division, Haleakala Field Station, Hawaii "Plants of Hawaii".
Fact sheet from "Common forest trees of Hawaii" (PDF format).
Excerpt from the book "Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide" (Motooka et al., 2003). (PDF format).

Additional online information about Leptospermum scoparium is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Leptospermum scoparium as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Leptospermum scoparium may be available from the Germplasm Resources Information Network (GRIN).

References:

Little, Elbert L./Skolmen, Roger G. 1989. Common forest trees of Hawaii (native and introduced). USDA Agriculture Handbook 679. Washington, D.C. 377 pp. + plates.

Motooka, Philip/Castro, Luisa/Nelson, Duane/Nagai, Guy/Ching, Lincoln. 2003. Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. 184 pp.

Motooka, Philip/Ching, Lincoln/Nagai, Guy. 2002. Herbicidal Weed Control Methods for Pasture and Natural Areas of Hawaii. Cooperative Extension Service, College of Tropical Agriculture and Human Resources, University of Hawai‘i. CTAHR free publication WC-8.

Neal, Marie C. 1965. In Gardens of Hawaii. Bernice P. Bishop Museum Special Publication 50, Bishop Museum Press. 924 pp.

Oppenheimer, Hank L. 2004. New Hawaiian plant records for 2003. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2003. Part 2: Notes. Bishop Museum Occasional Papers. 79:8-20.

Smith, Clifford W. 1985. Impact of Alien Plants on Hawai‘i's Native Biota. In: Stone, Charles P. and Scott, J. Michael, eds. Hawai‘i's terrestrial ecosystems: preservation and Management. Cooperative National Park Resources Studies Unit, University of Hawaii, Manoa.

Sykes, Bill. 0. Bill Sykes, pers. com.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.