Hedera helix L., Araliaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 10 (Go to the risk assessment)

Common name(s): [more details]

English: English ivy, ivy

Spanish: hiedra

Habit:  vine

Description: 

Genus: "Woody vines, creeping or climbing by adventitious roots. Leaves simple, alternate, stipules absent. Flowers perfect, in simple terminal umbels or racemes of umbellules; calyx a truncate rim or 5-toothed; petals 5, valvate; stamens 5; ovary inferior, 5-carpellate, surmounted by a convex disk; styles connate into a short stylopodium; stigmas sessile. Fruit a drupe, dark purple at maturity. Seeds 3-5 per fruit" (Wagner et al., 1999; p. 228)

Species: "Leaves of sterile branches broadly ovate, 3-5-lobed, 4-10 cm long, base cordate, those of fertile branches ovate to rhombic, entire, base obtuse to truncate. Inflorescence, calyx, and tips of young branches often pubescent with whitish, 5-6-branched, stellate hairs. Fruit globose, 5-8 mm long, the disk depressed-convex" (Wagner et al., 1999; p. 228).

"Climbing perennial.  Stems up to 30 m long, creeping or climbing, becoming stouter and ± erect and often arborescent at flowering; young shoots and petioles green to purplish or burgundy red, with few to numerous, (3)-6-16-(20)-rayed stellate or scale-like hairs.  Leaves glabrous, dark green or variegated ivory white; leaves of non-flowering shoots broadly ovate, obtuse to acuminate, obtuse to cordate at base, usually shallowly to moderately 3-5-palmately-lobed, (1.5)-3-15-(20) cm long; leaves of flowering shoots ovate, rhombic, or elliptic, often narrower and more crowded than leaves of non-flowering shoots, acute to acuminate, obtuse at base, not lobed, up to c. 15 cm long.  Inflorescence a raceme of numerous-flowered globose umbels; petals yellowish green, 3-5 mm long.  Flowers deep bluish purple to black when ripe, 2-3-seeded, 5-8 mm diameter"  (Webb et al., 1988; pp. 145-147).

Habitat/ecology:  Creeping along the ground or climbing over vegetation. "Blankets the ground in moist sheltered areas, prevents germination, excludes light, harbours disease, damages and brings down mature trees, changes the ecosystem"  (Weeds of Blue Mountains bushland).  In Hawai‘i, naturalized in the understory of mesic forests.  In New Zealand, in "waste places, riverbeds and stream banks, cliffs, often climbing over trees and fences" (Webb et al., 1988; pp. 145-147).

Propagation:  Seed; rooting from nodes. "Widely cultivated, often escaping and becoming established from vacant lots, cemeteries, and deserted homes.  The seeds are dispersed by birds which readily eat the fruits" (Webb et al., 1988; pp. 145-147).  "Birds eat the berries and excrete the seeds, often in bushland. Ivy also spreads vegetatively, by rooting at leaf nodes. It is also spread by garden rubbish dumping"  (Weeds of Blue Mountains bushland).

Native range:  Temperate Europe and Asia (Webb et al., 1988; pp. 145-147).

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 cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 228)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 228)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2003) (p. 24) East Maui. Vouchers cited: Starr & Martz 001218-1 (BISH), Starr & Martz 010419-1 (BISH), Starr & Martz 011026-1 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 228)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced cultivated	MacKee, H. S. (1994) (p. 18) Voucher cited: MacKee 31010

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 cultivated	Csurhes, S./Edwards, R. (1998) (p. 165)
Australia Australia (continental)	New South Wales	introduced invasive	Harley, Barbara (2009)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Owen, S. J. (1997)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 145)

Control:  Additional control information from the Bugwood Wiki.

Physical:  Repeated cutting of the vines.

Chemical:  The leaves have a waxy coating and most herbicides are ineffective. 

"1. Stump swab (all year round): metsulfuron-methyl 600g/kg (5g /L). Best for aerial vines.  Use a paint brush to liberally cover the cut surfaces within 15 minutes of cutting and all stem bases where exposed.
2. Spray (summer): glyphosate (10ml/L) or metsulfuron-methyl 600g/kg (5g/10L (knapsack) or 40g/100L (spraygun)) or Tordon Brushkiller (60ml/10L). Add penetrant to all mixes.  Do not use for ivy growing against trees"  (Weedbusters New Zealand).

Additional information:
Fact sheet from the Plant Conservation Alliance, Alien Plant Working Group.
Photos and additional information at the Environment Bay of Plenty, New Zealand, web site of the Bay of Plenty Regional Council.
Information from the Global Invasive Species Database.
Information from the publication "Nonnative invasive plants of Southern forests: A field guide for identification and control".
Information from the Southeast Exotic Pest Plant Council Invasive Plant Manual.
Information from the Bugwood Wiki.
Information and photos at Weeds of Blue Mountains bushland.
Information sheet from Weedbusters New Zealand.

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

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

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

References:

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Harley, Barbara. 2009. Weeds of Blue Mountains bushland. (booklet and online resource).

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

Miller, James H. 2003. Nonnative invasive plants of Southern forests: A field guide for identification and control. U.S. Department of Agriculture, Forest Service, Southern Research Station. Gen. Tech. Rep. SRS-62. 93 p.

Owen, S. J. 1997. Ecological weeds on conservation land in New Zealand: A database. Working draft. Wellington, New Zealand. Department of Conservation.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2003. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2001-2002. Part 2: Notes. Bishop Museum Occasional Papers. 74:23-34.

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).

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.