Prosopis juliflora (Sw.) DC., Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Hawai‘i/Pacific:  High risk, score: 19 (Go to the risk assessment)
Risk assessment from the Government of Queensland, Australia (PDF format).

Common name(s): [more details]

English: algaroba, ironwood, mesquite

French: algarrobe, algarrobe, bayarone

Spanish: algarroba, algarrobo, cují negro

Habit:  tree

Description:  "Shrubs or trees 3-10 m tall; branches slightly zigzag, with stout stipular spines 1-3 (-5) cm long.  Leaves with 1-2 (-4) pairs of pinnae, each with (6-) 12-25 (-29) pairs of leaflets, these oblong, 6-16 (-23) mm long, 1.5-3.2 (-5.5) mm wide, glabrous, apex rounded, obtuse, or subacute, base rounded.  Flowers numerous, in cylindrical spikes 5-10 (-15) cm long; corolla pale yellow, 4-5 mm long; stamens 5-8 mm long.  Pods pale yellowish brown, cylindrical or slightly irregularly curved, usually 8-30 cm long, 0.8-1.7 cm in diameter, mesocarp fleshy, only flattened in younger stages, stipe 0.7-2 cm long.  Seeds obovoid, 5-6.5 mm long, 4-5 mm wide"  (Wagner et al., 1999; pp. 692-693, 1878).

Habitat/ecology:  "Grass- and shrubland, dry forests.  This salt and drought tolerant tree is nitrogen-fixing and has deep reaching roots and tolerates dry as well as waterlogged soils.  The tree rapidly forms dense thorny thickets that reduce native species richness and wildlife habitats.  Invaded grasslands are transformed to woodland and forests.  Loss of grass cover under canopies of this tree may promote soil erosion.  The tree resprouts easily after damage"  (Weber, 2003; p. 344).

Naturalized in Hawai‘i  (Wagner et al., 1999; pp. 692-693); "occurs in dry leeward areas.  Capable of rendering large areas impassable and displacing lower-growing plants"  (Motooka et al., 2003).

Propagation:  Seed.  "Seed production is prolific, and seeds are dispersed by water and animals.  Seeds accumulate in a soil seed bank"  (Weber, 2003; p. 344).

Native range:  From Mexico through Central America to northern South America, Galápagos Islands.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Española Group	Española Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Española Group	Gardner por Española Islet, Española Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Pinta Group	Pinta Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santa Fé Group	Santa Fé Island	native	Charles Darwin Research Station (2005)
Ecuador (Galápagos Islands) Santiago Group	Rábida Island	native	Charles Darwin Research Station (2005)
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Naturalisée
French Polynesia Marquesas Islands	Ua Huka (Huahuna, Uahuka) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Naturalisée
French Polynesia Society Islands	Tahiti Island		Fosberg, F. R. (1997) (p. 53)
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Naturalisée
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Imada, Clyde T./Staples, George W./Herbst, Derral R. (2000) (p. 12) Voucher cited: C. Imada, W. Char & C. Morden 99-4 (BISH)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Oppenheimer, Hank (2007) (p. 24) Voucher cited: Oppenheimer & J. Penniman H50621 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 692)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced	ILDIS Co-ordinating Centre (2011)
Philippines Philippine Islands	Philippine Islands	introduced	ILDIS Co-ordinating Centre (2011)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Merrill, Elmer D. (1923) (p. 251) As Prosopis vidaliana Naves. Manila Bay region, forming dense thickets immediately back of the beach; also in Basilan.

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)	New South Wales	introduced invasive	Csurhes, S./Edwards, R. (1998) (p. 191)
Australia Australia (continental)	Queensland	introduced invasive	Australian Biological Resources Study (2011) "Occurs in a few localities near Townsville".
China China	China (People's Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
El Salvador El Salvador	El Salvador (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Honduras Honduras	Honduras (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Indonesia Indonesia	Indonesia (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Panama Panama	Panama (Republic of)	native	ILDIS Co-ordinating Centre (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced	ILDIS Co-ordinating Centre (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Lavergne, Christophe (2006) "Envahissant"
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Kueffer, C./Lavergne, C. (2004) (p. 4)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced	ILDIS Co-ordinating Centre (2011)

Comments:  P. juliflora is on the Hawai‘i state exclusion list.

Control: 

Physical:  "Seedlings and saplings can be pulled or dug out, roots must be removed.  Cutting trees below the ground surface may prevent resprouting.  Burning is used to kill plants above-ground"  (Weber, 2003; p. 344).

Chemical: "Sensitive to triclopyr. HAVO staff reported control with basal bark application of triclopyr ester at 5% product in diesel oil. (Chris Zimmer, HAVO). Small plants (to 5 ft) on Kaua‘i killed by foliar drizzle application of triclopyr ester at 15% in crop oil, but it took a year. Tebuthiuron was also effective (Motooka et al., 2003).

Additional information:
Excerpt from the book "Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide" (Motooka et al., 2003). (PDF format).
Information from the Purdue University NewCROP web site.
Information from the World Agroforestry Centre's AgroForestryTree Database.
Information from the Global Invasive Species Database.
"Mesquite in Queensland" from the Government of Queensland, Australia. (PDF format)
Weed Management Guide from the Government of Australia. (PDF format).
Information from the USDA Tropical Tree Seed Manual (PDF format).

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

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

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

References:

Australian Biological Resources Study. 2011. Flora of Australia Online. Australian Biological Resources Study, Canberra.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Comité français de l'Union Internationale pour la Conservation de la Nature en France. 2010. Les espéces envahissantes en outre-mer (online resource).

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2011. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

Fosberg, F. R. 1997. Preliminary checklist of the flowering plants and ferns of the Society Islands. Ed. by David R. Stoddart. U. Cal. Berkeley.

ILDIS Co-ordinating Centre. 2011. International Legume Database & Information Service. Online searchable database.

Imada, Clyde T./Staples, George W./Herbst, Derral R. 2000. New Hawaiian plant records for 1999. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1999. Part 1: Articles. Bishop Museum Occasional Papers. 63:9-16.

Kueffer, C./Lavergne, C. 2004. Case studies on the status of invasive woody plant species in the western Indian Ocean. 4. R233;union. Food and Agriculture Organization of the United Nations, Forestry Department, Forest Resources Division, Forest Resources Development Service, Working Paper FBS/4-4E. 37 pp.

Lavergne, Christophe. 2006. List des especes exotiques envahissantes a La Reunion. Unpublished manuscript (Excel file). .

McMullen, C. K. 1999. Flowering plants of the Galápagos. Comstock Pub. Assoc., Ithaca, N.Y. 370 p.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 2 [reprint]. Bureau of Printing, Manila. 530 pp.

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.

Oppenheimer, Hank. 2007. New plant records from Moloka‘i, Lāna‘i, Maui, and Hawai‘i for 2006. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2006. Part 2: Notes. Bishop Museum Occasional Papers 96:17-34.

Smith, Albert C. 1985. Flora Vitiensis nova: a new flora of Fiji. National Tropical Botanical Garden, Lawai, Kauai, Hawaii. Volume 3. 758 pp.

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).

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

Wiggins, I. L./Porter, D. M. 1971. Flora of the Galapágos Islands. Stanford University Press. 998 pp.