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 of Prosopis juliflora from the Government of Queensland, Australia (PDF format)

Common name(s): [more details]

English: algaroba, ironwood, mesquite

French: 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. (2013) Naturalisée
French Polynesia Marquesas Islands	Ua Huka (Huahuna, Uahuka) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) 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. (2013) 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 (2013)
Philippines Philippine Islands	Philippine Islands	introduced	ILDIS Co-ordinating Centre (2013)
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 (2013) "Occurs in a few localities near Townsville".
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	native	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)	native	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	ILDIS Co-ordinating Centre (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	ILDIS Co-ordinating Centre (2013)
China China	China (People's Republic of)	introduced	ILDIS Co-ordinating Centre (2013)
Indonesia Indonesia	Indonesia (Republic of)	introduced	ILDIS Co-ordinating Centre (2013)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	introduced	ILDIS Co-ordinating Centre (2013)

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 (2013)

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).