Acacia dealbata Link, Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 22 (Go to the risk assessment)

Common name(s): [more details]

Chinese: yin jing

English: mimosa, silver wattle, Sydney black wattle

French: acacia bernier, mimosa argenté, mimosa de Bormes

Spanish: acacia francesa, aromo, aromo de castilla, aromo del pais

Habit:  shrub/tree

Description:  "Shrub to large tree; twigs ribbed, densely puberulent. Leaves 2-pinnate, alternate, densely puberulent on rachis and sparsely hairy on pinnules; pinnae in (6)-10-21 pairs; pinnules in 25-40-(50) pairs, fairly close set, glaucous, narrow-oblong, obtuse or subacute, entire, 2-4-(7) x c. 0.75 mm; petiole (5)-10-20 mm long; stipules inconspicuous; solitary glands present between each pair of pinnae, usually except basal pair. Inflorescence of numerous, many-flowered, medium yellow, globose heads arranged in axillary, compound racemes ± = leaves. Flowers 5-merous, sessile. Pod glabrous, ± straight, 50-100 x 8-12 mm; aril scarcely folded, thickened to one side of seed.  Leaves of seedlings usually differ markedly from those of mature trees in being less glaucous, having fewer pinnae and fewer and larger pinnules. However, the distribution of glands and stem hairiness is the same as that of mature trees. Some flowering specimens have leaf forms similar to those of seedlings; again stem hairs and gland distribution distinguish these specimens"  (Webb et al., 1988; 705).

Description from Flora of Australia online.
Description from Flora of China online.

Habitat/ecology:  "Where native, this plant grows as a tall tree in mountain forests and along watercourses and in dry sclerophyll forests, remaining shrubby under dry conditions.  It forms dense thickets that suppress native vegetation, disrupt water flow and increase erosion along streambanks.  The plant is nitrogen-fixing and increases soil fertility"  (Weber, 2003; p. 14).

In New Zealand, "waste places, scrubland, riverbeds. In many areas silver wattle forms dense stands by suckering"  (Webb et al., 1988; 705).  "In Chile this species grows in the following environmental conditions:  Low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m.  Somewhat dry areas where the drought may last 3-5 months, precipitations of 400-800 mm. are concentrated in winter; humid areas, with almost constant rainfall, short dry periods are possible (generally not longer than 1 month).  Fully exposed to the sun, level areas or slopes facing north; some shadow, some protection against direct sunlight, some shadow from vegetation, filtering about 20 - 40 % of light"  (Chileflora).

Propagation:  Seed

Native range:  Southeast Australia, Tasmania (Webb et al., 1988; 705).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive cultivated	Australian Biological Resources Study (2011) Voucher cited: R.O. Gardner 6186 (AK, K) Cultivated as an ornamental and sometimes seeding itself
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 461, 465, 550)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 461, 465, 550) Voucher cited: Danton G(1474bis)1239bis
French Polynesia Society Islands	Tahiti Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Cultivée

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)	Australia (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011) Australian Capital Territory, Tasmania, Victoria
Australia Australia (continental)	New South Wales	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Chile (continental) Chile	Chile (Republic of)	introduced invasive	Belov, Michail (2011) "This is an exotic plant, very invasive in central areas of Chile".
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) Fujian, Guangxi, Guizhou, Sichuan, Yunnan, Zhejiang
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (pp. 129-130)
Costa Rica Costa Rica	Costa Rica (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Guatemala Guatemala	Guatemala (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 705)
Taiwan Taiwan	Taiwan Island	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (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 cultivated	Comité français de l'Union Internationale pour la Conservation de la Nature en France (2010) foresterie, envahissant
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced	ILDIS Co-ordinating Centre (2011)

Control:  "Mechanical control is achieved by ringbarking or digging out, chemical control by basal stem treatments, stump treatments, or foliar spray with herbicides.  After clearing large infestations, a follow-up programme is necessary to remove emerging seedlings and to prevent coppice regrowth.  Stumps need to be treated with herbicides in order to prevent resprouting, and it is recommended to keep stumps lower than 15 cm"  (Weber, 2003; p. 14).

Additional information:
Photos and other information from Chileflora.
Fact sheet from World Wide Wattle.
Fact sheet from Florabase.
Fact sheet from Florabank.
Fact sheet from DAISIE.
Fact sheet from the California Invasive Plant Council.

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

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

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

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

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

Belov, Michail. 2011. Chileflora (online resource).

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

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

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).

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

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

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

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.

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

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).