Senecio madagascariensis Poir., Asteraceae

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Present on Pacific Islands?  no

Threat only at high elevations?  no

Risk assessment results: 

Reject, score: 15 (Go to the risk assessment (Australia))
High risk, score: 23 (Go to the risk assessment (Pacific))

Common name(s): [more details]

English: fireweed, Madagascar fireweed, Madagascar ragwort, variable groundsel

Habit:  herb

Description:  "An erect hairless annual or short-lived perennial herb 10 to 70 cm high, reproducing from the crown and by seed.  Stems erect, slender, 1 to many arising from the crown, 10 to 70, usually 10 to 50 cm high, branching above.  Leaves bright green; alternate, of variable size and shape, often narrow and rather fleshy, 2 to 8, usually 2 to 6 cm long, the broader leaf bases generally clasped around the stem; margins serrate, entire or lobed.  Flowers bright yellow, consisting of 13 ligulate ray florets, oblong to obovate, 10 mm long, and numerous tubular disc florets grouped into heads 15 to 20 mm diameter, each subtended by an involucre of 20 or 21 bracts; heads arranged in clusters at the ends of branches.  Seeds brownish, cylindrical, 1.5 to 3 mm long; covered with lines of short white hairs and crowned by a pappus of silky hairs. Root:  A shallow branching annual or perennial taproot with numerous fibrous laterals all within the upper 20 cm of soil"  (Parsons and Cuthbertson, 1992; pp. 304-305).

Habitat/ecology:  Subhumid to humid subtropical woodland on a wide range of soils (Parsons and Cuthbertson, 1992; pp. 304-305).

Propagation:  Seed, spread by wind, birds, animals and man (as a contaminant in hay and grain or on machinery). Spreads locally by rooting from nodes.

Native range:  South Africa.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 24) Vouchers cited: S. Perlman et al. 10312 (PTBG, US), T. Flynn & D. Lorence 3080 (PTBG), W. Shishido s.n. (BISH)
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 33) Vouchers cited: Starr, Starr & Tokishi 040330-3 (BISH), Starr, Starr & Higashino 040511-1 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 24) Vouchers cited: L. Hume 497 (BISH, PTBG, US), W. L. Wagner & T. Flynn 6321 (BISH, US)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 33) Voucher cited: Starr, Starr, Anderson & Anderson 050623-2 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Martz, Kim/Loope, Lloyd L. (1999) (p. 11) East Maui. Voucher cited: Starr & Martz 980215-71 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, Randal T. (2002) (p. 4) West Maui. Voucher cited: Oppenheimer H30004 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Herbst, Derral R./Staples, George W./Imada, Clyde T. (2004) (p. 4) Vouchers cited: D. Arakaki s.n. (BISH 668939), K. Kawelo s.n. (BISH 695026), K. Kawelo s.n. (BISH 695028)

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	Motooka, Philip/Castro, Luisa/Nelson, Duane/Nagai, Guy/Ching, Lincoln (2003) "A serious pasture problem".
Australia Australia (continental)	Queensland	introduced invasive	Motooka, Philip/Castro, Luisa/Nelson, Duane/Nagai, Guy/Ching, Lincoln (2003) "A serious pasture problem".

Comments:  On the State of Hawai‘i noxious weed list.  Toxic to livestock.

Control: 

Physical:  "Resting pastures is reported by rancher Polo Von Holt to control ragwort in his pastures in Kohala.  Ragwort can be controlled by grazing by sheep and goats, but too high a diet of fireweed will cause illness or death of these animals"  (Motooka et al., 2003).

Chemical:  "Very susceptible to 2,4-D, dicamba, MCPA, metsulfuron, and triclopyr when young and succulent.  Susceptible to glyphosate, although only application with wipe-on applicators to taller ragwort is possible to avoid injury to pasture species.  Mature ragwort susceptible to MCPA at 2 lb/acre, clopyralid at 0.5 lb/acre.  Tebuthiuron at 2 lb/acre effective.  Follow-up sowing of forage seed is recommended to reclaim the site and compete with regenerating ragwort.  Continuing monitoring is needed to control newly emerging seedlings before seed set"  (Motooka et al., 2003).

Biological:  "HDOA is evaluating biocontrol agents for controlling ragwort"  (Motooka et al., 2003).

Additional information:
Information from the book "Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide" (Motooka et al., 2003). (PDF format).
1-page info sheet from HEAR
CTAHR (UH) Control of fireweed from CTAHR, University of Hawaii
Fireweed fact sheet from "Burke's Backyard"
Fireweed (Senecio madagascariensis) Pest Facts sheet  from Queensland (Australia) Department of Natural Resources
All of the above are in PDF format.

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

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

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

References:

Herbst, Derral R./Staples, George W./Imada, Clyde T. 2004. New Hawaiian plant records for 2002-2003. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2003. Part 1: Articles. Bishop Museum Occasional Papers. 78:3-12.

Lorence, David H./Flynn, Timothy W./Wagner, Warren L. 1995. Contributions to the flora of Hawai‘i. III. New additions, range extensions, and rediscoveries of flowering plants. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1994. Part 1: Articles. Bishop Museum Occasional Papers. 41:19-58.

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.

Oppenheimer, Hank L./Bartlett, Randal T. 2002. New plant records from the main Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:1-14.

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

Starr, Forest/Martz, Kim/Loope, Lloyd L. 1999. New plant records from East Maui for 1998. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 2: Notes. Bishop Museum Occasional Papers. 59:11-15.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2006. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:31-43.

U.S. Dept. Agr., Agr. Res. Serv. 2008. 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).