Rubus argutus Link, Rosaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 21.5 (Go to the risk assessment)

Other Latin names:  Rubus penetrans L. H. Bailey

Common name(s): [more details]

English: Florida prickly blackberry, highbush blackberry, prickly Florida blackberry

Hawaiian: ōhelo ‘ele ‘ele

Habit:  shrub

Description:  "Erect or becoming arching shrubs; stems stiff and usually erect in open areas, more or less decumbent in shaded sites, primocanes 10-30 dm long, angled, covered with stout, straight or hooked prickles up to 6 (-8) mm long, their bases usually longitudinally elongated, also sparsely pilose, lateral branches of floricanes moderately to densely pilose, prickles usually smaller.  Pimocane leaves palmately compound, leaflets (3) 5, all similarly shaped, elliptic, oblong-oblanceolate, or ovate, the terminal one usually 8-13 cm long, 3.5-5 (-8) cm wide, upper surface glabrate, lower surface usually soft pilose and midrib usually with small prickles, margins coarsely and irregularly serrate, terminal leaflet with longest petiolule usually 2-4 cm long, petiolules and petioles usually pilose and with prickles; floricane leaves similar to those of primocanes but smaller, leaflets 3 (5), the terminal one usually only 5-9 cm long.  Flowers in short, open racemes, pedicels 15-20 mm long, moderately to densely villous (hairs not glandular or sometimes some of them glandular) and with prickles; petals white, obovate, 13-20 mm long.  Fruit black at maturity, subglobose to oblong, 1.5-2 cm long, cohering to the tardily separating receptacle" (Wagner et al., 1999; pp. 1107, 1890).

Habitat/ecology:  "Grassland, forests and forest edges.  Native habitats of this shrub include wet or swampy woodlands, often in standing water, streambanks, shoreline thickets, but also dry places.  It forms impenetrable thickets by its arching stems that become rooted at the tips.  Native plants are eliminated and wildlife movement is affected.  Seedlings of shrubs and trees are unable to establish in areas invaded by this shrub.  The shrub easily resprouts from basal and belowground buds after damage"  (Weber, 2003; p. 368).  "Smothers low plants and shrubs.  Blocks passage on trails"  (Motooka et al., 2003).

In Hawai‘i, "an extremely serious weed naturalized in a variety of disturbed habitats, including mesic to wet forest and subalpine grassland, 200-2,300 m" (Wagner et al., 1999; p. 1107). 

Propagation:  Seed, spread by birds and other animals; locally by rooting of aerial shoots where they bend over and touch the ground.

Native range:  Central and eastern United States (Wagner et al., 1999; p. 1107).

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	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1107-1108)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1107-1108)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1107-1108)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Hughes, Guy D'Oyly (1995) (p. 9) Voucher cited: Hughes 9 (BISH) Naturalized sporadically in wet forest from 700-1120 m elevation.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1107-1108)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 1124) "Wasteland, roadsides, streamsides".

Control:  Additional control information from the Bugwood Wiki.

Physical: The aerial portions of a plant are normally destroyed by fire but the plant quickly recovers from basal and subterranean shoots. Isolated plants may be grubbed out, but any remaining roots will sprout.

Chemical:  "Sensitive to foliar applications of triclopyr and picloram; dicamba not effective.  Sensitive to metsulfuron.  Susceptible to drizzle applications of triclopyr and of glyphosate in trail work on the Nāpali coast of Kaua‘i.  Chris Zimmer and Tim Tunison at HAVO reported triclopyr amine at 0.5% of product without surfactant, sprayed to wet foliage, was effective.  Pat Bily (TNC) confirmed triclopyr amine at 0.5% of product without surfactant effective.  Bily also reported 10% triclopyr ester product in vegetable-oil based carrier applied to 2-3 inches at base of each cane very effective" (Motooka et al., 2003).

Biological: Biological control of R. argutus in Hawai‘i by Croesia zimmermani Clark (Lepidoptera: Tortricidae) has been effective in pasture and open areas but of limited effect in forests (Julien, 1992; pp. 83-84).  "In the 1960s several insects were introduced in Hawaii as biological control agents against blackberry (Rubus argutus): Priophorus morio (Hymenoptera), Schreckensteinia festaliella (Lepidoptera), Croesia zimmermani (Lepidoptera), Apotoforma sp. (Lepidoptera), Bembecia marginata (Lepidoptera), and Chlamisus gibbosa (Chrysomelidae). In general, the insects have not been effective biological control agents, although the leaf roller Schreckensteinia festaliella has damaged blackberry in some areas despite being subjected to high incidence of egg parasitism. At least three of the insects which became established also attack native species Rubus hawaiiensis and Rubus macraei. The rust fungus Gymnoconia nitens attacks Rubus spp. in North America, and was studied as a potential biological control agent for Hawaii. The rust was not recommended for release because it also attacked native Rubus species"  (Smith et al., 2002).