Rubus discolor Weihe & Nees, Rosaceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Risk assessment results:  High risk, score: 24 (Go to the risk assessment)

Other Latin names:  Rubus armeniacus Focke

Common name(s): [more details]

English: Himalaya blackberry

Habit:  shrub

Description:  "A robust, sprawling, more or less evergreen, glandless shrub.  The shrubs appear as "great mounds or banks" (Bailey, 1945), with some of the canes standing up to 3 m tall.  Other canes are decumbent, trailing or scandent up to 20-40 feet long (Bailey, 1923), frequently taking root at the tips.  The pimocanes are pilose-pubescent, becoming nearly glabrous with age.  These are strongly angled and furrowed, bearing well-spaced, heavy, broad-based, straight or somewhat curved prickles 6-10 mm long.  Pimocane leaves are 5-foliate, glabrous above when mature and cano-pubescent to cano-tomentose beneath.  There are hooked prickles on the petioles and petiolules.  The leaflets are large and broad with the terminal leaflet roundish to broad oblong.  Leaflets are abruptly narrowed at the apex, unequally and coarsely serrate-dentate.  Floricane leaflets are 3-5 foliate and smaller than on the pimocanes.  The inflorescence is a large terminal cluster with branches in the lower axils.  The peduncles and pedicels are cano-tomentose and prickly.  The flowers are white or rose colored, 2-2.5 cm across, with broad petals.  Sepals are broad, cano-tomentose, conspicuously pointed and soon reflexed, approximately 7-8 mm long.  The roundish fruit is black and shiny, up to 2 cm long, with large succulent drupelets"  (Starr, Starr & Loope, 2003; p. 2).

Habitat/ecology:  "Wastelands, pastures, forest plantations, along roads, creek gullies, river flats and fence lines"  (Starr, Starr & Loope, 2003; p. 2).

Propagation:  Seed and cuttings. Canes root at tips (Starr, Starr & Loope, 2003; pp. 2-3).

Native range:  Western Europe (Starr, Starr & Loope, 2003; pp. 3).

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	Maui Island	introduced cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1106) West Maui. Voucher cited: Krauss 1136 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1106)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Conant, Patrick (1996) (p. 2) Voucher cited: P. Conant & L. Nagasawa s.n. (BISH)

Control:  Management information on the Global Invasive Species Database.

Physical: "Mechanical control of this species is tough due to sharp prickles and large thickets. It may be possible to pull or dig up small seedlings. The entire plant, above and below ground, must be carefully removed to prevent re-growth. Plants are sometimes cut back to reduce biomass before chemical control is done".

Chemical: "Various forms of chemical methods can be used to control Rubus discolor, including foliar, stem injection, cut stump and basal stem methods using glyphosate or triclopyr products. Plants on East Maui [Hawaii] have been treated with a 10% Garlon 4 in oil basal stem method (P. Bily pers. comm.)".

Biological: "Several biological control agents have been introduced to Hawai‘ for the related species, Rubus argutus (prickly Florida blackberry). None are known for Rubus discolor" (Starr, Starr & Loope, 2003; p. 4).

Additional information:  Report on Rubus discolor from US Geological Survey, Biological Resources Division, Haleakala Field Station, Hawaii "Plants of Hawaii".
Profile on the Global Invasive Species Database
Plant assessment from the California Exotic Pest Plant Council
"Controlling Himalaya blackberry in the Pacific Northwest" from The Nature Conservancy

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

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

References:

Conant, Patrick. 1996. New Hawaiian pest plant records for 1995. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1995. Part 2: Notes. Bishop Museum Occasional Papers. 46:1-2.

U. S. Government. 2006. Integrated Taxonomic Information System (ITIS) (on-line resource).

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).