Watsonia meriana (L.) Mill., Iridaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Antholyza meriana L.; Watsonia bulbillifera J. W. Mathews & L. Bolus

Common name(s): [more details]

English: bulbil bugle-lily, bulbil watsonia, wild watsonia

Habit:  herb

Description:  "Plants sometimes growing in dense clumps, 50-200 cm. Corms tunicate, depressed-globose, 30-45 mm in diameter; tunic fibrous, fibers coarse, reticulate. Stems simple or 1-2-branched, often with large cormlets in proximal axils, occasionally also in distal axils of stem, spike. Leaves 4-6, basal leaves 3-4, blade lanceolate, 12-35 mm wide; cauline leaves smaller than basal, blade with margins and midribs hyaline, heavily thickened. Spikes 8-12(-25)-flowered; spathes often flushed with red, outer 18-30 mm, dry in distal 3-5 mm, inner slightly longer to slightly shorter than outer. Tepals orange, red, or purple, lanceolate, outer slightly narrower than inner, 22-27 x 8-15 mm; perianth tube proximally slender, 18-25 mm wide, abruptly expanded distally, 20-25 mm wide; filaments 35-45 mm; anthers 8-12 mm; ovary oblong, 3-4 mm; style branching opposite middle of anthers; branches 6-7 mm. Capsules 22-30 mm. Seeds prominently winged distally, weakly or not winged proximally, 10-18 mm"  (Flora of North America online).

Habitat/ecology:  "Heath- and woodland, riparian habitats, freshwater wetlands, coastal dunes.  This plant favors moist situations and will withstand flooding for several weeks.  It grows to dense stands that prevent the regeneration of overstorey species and reduce native plant species richness"  (Weber, 2003; p. 454).

In U.S. (California), "roadsides and grassy banks"  (Flora of North America online).  In New South Wales, Australia, "locally abundant weed of roadsides, unimproved pastures and wasteland; chiefly coastal districts"  (NSW PlantNET).

Propagation:  Cormlets; occasionally by seed. "Most Watsonia plants recorded from North America correspond to the triploid, sexually sterile form of W. meriana, also known as W. bulbillifera, which reproduces by means of cormlets produced at the aerial nodes. Most of the flowers do not produce capsules, but a few, containing viable seeds, are occasionally formed"  (Flora of North America online).  Spreads mainly via axillary bulbils (Oppenheimer, 2004; p. 12).  Cormlets are dispersed by water and in soil  (Weber, 2003; p. 454).

Native range:  South Africa (western Cape Province) (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
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 cultivated	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 502, 548, 558) Voucher cited: Danton I(5/55)1439. "En RC, está presente mezclada con W. borbonica (Poir.) Goldb., en menor cantidad, en el pueblo de San Juan Bautista".
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2004) (p. 12) East Maui. Voucher cited: Oppenheimer, E. Duvall & L. Nelson H40203 (BISH)

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	National Herbarium of New South Wales (2013)
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Healy, A. J./Edgar, E. (1980) (p. 139)
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	Flora of North America Editorial Committee, eds. (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 cultivated	Lavergne, Christophe (2006) "Cultivé/Naturalisé"

Control: 

Physical:  "Isolated plants can be hand pulled or grubbed at any time before cormlets are forming.  Mowing or slashing kills the topgrowth but does not affect the corms in the soil.  Cutting at 10-15 cm height when the stems first emerge but before they elongate prevents formation of cormlets"

Chemical:  "An effective herbicide is 2,2-DPA applied before the first flowers are formed"  (Weber, 2003; p. 454).