Baccharis halimifolia L., Asteraceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 19 (Go to the risk assessment)

Common name(s): [more details]

English: eastern baccharis, groundsel bush, groundsel tree, Sea Island myrtle, tree groundsel, waterbrush

Habit:  shrub

Description: 

Genus:  "Dioecious, sometimes evergreen shrubs, in North and South America; leaves alternate, sometimes lacking; flower heads small, discoid, in panicles; flowers all rubular, white or yellowish; achenes 4-10-nerved, pappus of white capillary bristles, many in the female flowers, few in the male" (Bailey & Bailey, 1976; p. 133).

Species:  "A branching glabrous shrub to about  3 m tall; branchlets angled, sometimes minutely scurfy.  Leaves with somewhat margined petioles to about 1 cm long; blades obovate to elliptic or oblanceolate, those of the stem and lower branches 2-7 cm long and 1-5 cm wide, those of the branchlets smaller, cuneate at base, obtuse to acute at apex, glandular-dotted, typically coarsely several-toothed above the middle.  Heads white, in terminal or axillary clusters of 1 to 5, those of the staminate plant nearly globose when young.  Involucres campanulate, 4-6 mm high. Phyllaries imbricated in several series, glutinous, the outer ones ovate-elliptic and obtuse, the inner ones of the pistillate heads lanceolate and acute to acuminate.  Achenes about 1.5 mm long; pappus bright-white, 6-8 mm long, noticeable exceeding the involucre" (Correll & Correll, 1982; p. 1456).

Habitat/ecology:  "Coastal marshes... Resistant to salt spray..." (Bailey & Bailey, 1976; p. 133).  "In open marshes, coppices and on open gravelly flats and in palm flats" (Correll & Correll, 1982; p. 1456).  "Coastal swamps, coastal forests, disturbed places.  In the native range, this shrub is found mostly in coastal habitats, e.g. salt marshes and tidal rivers, sandy places, but also on disturbed places far off the coast.  In the cooler parts within the native range, the shrub is deciduous. The shrub tolerates a high level of soil salinity"  (Weber, 2003; p. 65).

Propagation:  Seed, dispersed by wind and water (Weber, 2003; p. 65).

Native range:  US, Central America (Bailey & Bailey, 1976; p. 133).  "Eastern and southeastern United States, and the West Indies" (Correll & Correll, 1982; p. 1456).

Presence:

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)		Parsons, W. T./Cuthbertson, E. G. (1992)
Australia Australia (continental)	Queensland	introduced invasive	Queensland Herbarium (2002) (p. 1)
Mexico Mexico	Mexico (United Mexican States)	native	Weber, Ewald (2003) (p. 65)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 182) "Open hillsides, rock crevices and waste places".

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Control: 

Physical:  "If plants are removed manually, the roots should be cut well below the surface to prevent resprouting.

Chemical:  "Chemical control is done by spraying herbicides containing 2,4-D, dicamba plus MCPA, glyphosate, or picloram plus 2,4-D"  (Weber, 2003; p. 65).

Additional information:
Fact sheet from the Government of Queensland, Australia. (PDF format).

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

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

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

References:

Bailey, L. H./Bailey, E. Z. 1976. Hortus third: A concise dictionary of plants cultivated in the United States and Canada. Macmillan, New York. 1290 pp.

Correll, Donivan S./Correll, Helen B. 1982. Flora of the Bahama Archipelago. Gantner Verlag.

Cronk, Q. C. B./Fuller, J. L. 2001. Plant invaders. Earthscan Publications, Ltd., London. 241 pp.

Parsons, W. T./Cuthbertson, E. G. 1992. Noxious weeds of Australia. Inkata Press, Melbourne/Sydney. 692 pp.

Queensland Herbarium. 2002. Invasive Naturalised Plants in Southeast Queensland, alphabetical by genus. Modified from: Batianoff, George N. and Butler, Don W. (2002). Assessment of Invasive naturalized plants in south-east Queensland. Appendix. Plant Protection Quarterly 17, 27-34. 11 pp.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

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.