Verbascum thapsus L., Scrophulariaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Risk assessment results:  High risk, score: 11 (Go to the risk assessment)

Common name(s): [more details]

Chinese: mao rui hua

English: Aaron's rod, big taper, common mullein, flannel mullein, flannel plant, flannelleaf, great mullein, hag taper, mullein, torches, velvet dock, velvet plant, woolly mullein

French: bouillon blanc, grande molène, molène

Spanish: gordolobo común, guardalobo, hierba del Paño

Habit:  herb

Description:  "Stout biennial herbs 3-20 dm tall in the second year, densely yellowish woolly tomentose throughout, the hairs stellate or dendritic.  Basal leaves obovate to oblanceolate, 8-50 cm long, 2.5-14 cm wide, densely yellowish or whitish woolly tomentose, margins entire to shallowly crenate; cauline leaves becoming progressively smaller toward the inflorescence, oblanceolate, sessile and decurrent on stem.  Flowers in compact, spike-like panicles, pedicels partly adnate to the stem; calyx (5-) 8-12 mm long, the lobes lanceolate; corolla yellow, rarely white, 8-15 mm long, scurfy pubescent externally, sometimes also ciliate, the hairs stellate; upper 3 staminal filaments villous with yellow hairs, the lower 2 glabrous to sparsely villous.  Capsules broadly ovoid to elliptic-ovoid, 0.7-1 cm long, densely tomentose with stellate or branched hairs"  (Wagner et al., 1999; p. 1247).

Habitat/ecology:  "Grassland, riparian habitats, disturbed sites.  This plant is found mainly on dry sandy soils and primarily colonizes sites of low fertility.  It forms dense patches with the large rosettes that shad out native plants.  The plant spreads rapidly after disturbances and forms a continuous cover, eliminating the native vegetation"  (Weber, 2003; p. 448).

In Hawai‘i, "naturalized and sometimes locally common, usually in open sites, cinder cones, subalpine woodland and shrubland to alpine desert, 1,550-2,350 m" (Wagner et al., 1999; p. 1247). In New Zealand, "poor stony or gravelly pastures, screes, stony river beds, roadsides and railways, shingle river banks and beds, dry waste places, sea level to c. 1000 m" (Webb et al., 1988; p. 1205).  "In Chile this species grows in the following environmental conditions:  Medium altitude up to the timber line; 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; dry, arid areas, with long drought periods of 6-10 months, precipitations of 100 mm-300 mm. are concentrated in winter.  Fully exposed to the sun, level areas or slopes facing north"  (Chileflora).

Propagation:  Seed.  "The long-lived seeds may remain viable in the soil for several decades.  Once exposed to light they germinate rapidly"  (Weber, 2003; p. 448).

Native range:  Eurasia (Wagner et al., 1999; p. 1247).

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	Orchard, Anthony E., ed. (1994) (p. 10) "Probably introduced as a garden plant but now occasionally naturalised". Vouchers cited: W.R. Sykes NI 368 (CHR); 1898, I. Robinson (NSW)
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) (p. 558)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1247) Voucher cited: L. W. Bryan s.n. (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1247) Subject of an eradication program, may no longer be present.

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)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 189)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 1205)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	Belov, Michail (2013)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced invasive	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	introduced invasive	U.S. Dept. Agr., Nat. Res. Cons. Serv. (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	Baret, Stephane/Rouget, Mathieu/Richardson, David M./Lavergne, Christophe/Egoh, Benis/Dupont, Joel/Strasberg, Dominique (2006) (p. 758)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Canada Canada	Canada	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast) United States (other states)	USA (Florida)	introduced invasive	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control:  Additional control information from the Bugwood Wiki.

Physical:  "Individual plants can be killed by cutting c. 8 cm below the soil surface to remove the top of the taproot.  Cutting stands before seed set prevents dispersal and burial of seeds".  (Weber, 2003; p. 448).  "Pulling a digging out roots was effective but labor-intensive and soil disturbing (Chris Zimmer, HAVO).  Plants are best controlled during the rosette stage.  Goats browse on mullein"  (Motooka et al., 2003).

Chemical:  "Chemical control is done by spraying rosettes with 2,4-D, glyphosate or tebuthiuron.  Repeated applications may be necessary to control regrowth"  (Weber, 2003; p. 448).  "Very sensitive to metsulfuron at 0.1 oz./acre.  Young plants sensitive to 2,4-D and glyphosate.  HAVO staff have controlled mullein with glyphosate at 1% of product in water formulation in foliar application (Chris Zimmer, HAVO)"  (Motooka et al., 2003).