Agapanthus praecox Willd., Amaryllidaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 12 (Go to the risk assessment)

Other Latin names:  Agapanthus orientalis F. M. Leight. [≡ Agapanthus praecox subsp. orientalis]

Common name(s): [more details]

English: African-lily, agapanthus

Habit:  herb

Description:  "A herb with flowering stalks of 75-100 cm height and with a thick and branched rhizome.  The broad to narrowly lanceolate leaves are 40-80 cm long, 3-5 cm wide and emerge from a rosette.  Inflorescences are large single umbels at the end of tall and hollow scapes of 50-100 cm length.  Umbels are dense and contain numerous blue or white flowers on pedicels of 5-8 cm length.  The blue to white perianth is 4-5 cm long and has dark midveins on the six segments.  Stamens are 4-4.5 cm long, the anthers are 3-5 mm long and yellow.  The fruit is an elongated ovoid capsule of 25-33 mm length, containing numerous black seeds that have a membranous wing and measure 7-8 mm in length"  (Weber, 2003; p. 25).

"Evergreen herb, usually forming dense clumps.  Leaves to 20, strap-shaped, 8-28 x to 2 inches, arching over, channeled.  Inflorescence a many-flowered umbel, ±dense, scape 16-40 inches tall, pedicels 2-5 inches long.  Flowers 1.5-2 inches long, white or blue; tepal bases shortly tubular, lobes spreading, thing-textured, margins ñruffled; stamen and style included.  Fruit ellipsoid, 3-angled, papery"  (Staples & Herbst, 2005; p. 678).

Habitat/ecology:  "Coastal sand dunes, grass- and heathland, riparian habitats, forests, rock outcrops.  Forms dense populations that crowd out native vegetation and reduce species richness.  After establishment, it quickly forms dense clumps, and scattered clumps collate into a single matrix dominated by this species"  (Weber, 2003; p. 25).  Has low water requirements  (Staples & Herbst, 2005; p. 678).  "Tough, hardy, likes full sun, grows in almost any soil, almost anywhere.  Spreads rapidly down drainage lines, but will also grow in dry areas. Dense clumping roots displace all other vegetation" (Weeds of Blue Mountain bushland).

Propagation:  "Numerous small black shiny seeds are produced in a 5cm three-sided capsule, end of summer into autumn.  The underground structure (rhizome, poisonous) forms large continually extending clumps, and seed washes down waterways. Agapanthus is also frequently dumped on bushland edges"  (Weeds of Blue Mountain bushland).

Native range:  Cape region of South Africa  (Staples & Herbst, 2005; p. 678).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Cook Islands Southern Cook Islands	Rarotonga Island	introduced cultivated	McCormack, Gerald (2013)
Guam Guam Island	Guam Island	introduced	Raulerson, L. (2006) (p. 19) Agapanthus sp.
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (1943) (voucher ID: BISH 120944) Taxon name on voucher: Agapanthus praecox subsp. orientalis (Leighton) Leighton
State of Hawaii Hawaiian Islands	Kaua‘i Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (1987) (voucher ID: BISH 511507) Taxon name on voucher: Agapanthus praecox subsp. orientalis (Leighton) Leighton
State of Hawaii Hawaiian Islands	O‘ahu Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (1932) (voucher ID: BISH 120943) Taxon name on voucher: Agapanthus praecox subsp. orientalis (Leighton) Leighton
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced cultivated	Vander Velde, Nancy (2003) (p. 41) Rare or extirpated. Not seen since 1991.
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced cultivated	MacKee, H. S. (1994) (p. 92) subsp. orientalis (F. M. Leight.) F. M. Leight. (as Agapanthus orientalis Leighton)

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	Harley, Barbara (2009)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Healy, A. J./Edgar, E. (1980) (p. 47) As Agapanthus orientalis. Voucher cited: R. Mason and N. T. Moar 2150 (CHR 81051)
New Zealand New Zealand	New Zealand (country)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) subsp. orientalis (F. M. Leight.) F. M. Leight.
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control: 

Physical:  "Dig out scattered plants. Dispose of corms and root fragments at a refuse transfer station or dry them out and burn them. Usually follow up with spraying."

Chemical:  "1. Spray: metsulferon-methyl 600g/kg (4g) + glyphosate (200ml) + penetrant /10L water.  2. Cut down and paint stump: slash leaves close to ground, leave on site to rot down. Treat fresh bases with metsulferon-methyl 600g/kg (1g) + glyphosate (50ml) + penetrant /L or a 3-5mm layer of Vigilant gel.

Plants often resprout and seed bank reinfests bared sites thickly, so follow up frequently until eradicated. At least 3-4 follow up treatments are needed. Begin eradication at top of banks and work down. Don't replant until after 2-3 treatments"  (Weedbusters New Zealand).