Himalayan Blackberry (Rubus armeniacus)

23 October 2015: Walked about Willamette Mission State Park in Wheatland, Oregon, and came across Himalayan Blackberry (Rubus armeniacus). Himalayan Blackberry is a major invasive species of the Pacific Northwest and many past and current efforts exist to rid the region of its noxious characteristics or tendencies. One such report in 2004 by the Nature Conservancy stated the following: "Himalayan blackberry (generally known scientifically as Rubus discolor, R. procerus or R. fruticose, but technically R. armeniacus) is a robust, perennial, sprawling, more or less evergreen, shrub of the Rose family (Rosaceae). Leaves are large, round to oblong and toothed, and typically come in sets of three (side shoots) or five (main stems). The most characteristic feature is probably the robust stems supporting large, stiff prickles."

The same Nature Conservancy 2004 report added that: "Contrary to its common name, Himalayan blackberry (HBB) is a native of Western Europe. HBB was probably first introduced to
North America in 1885 as a cultivated crop. By 1945 it had naturalized along the West Coast. HBB occurs on both acidic and alkaline soils, mainly in areas with an average annual rainfall greater than 76 cm (29 inches) at altitudes up to 1800 meters (6000 feet). It thrives and may form impenetrable thickets in wastelands, pastures, forest plantations, roadsides, creek gullies, river flats, riparian areas, fence lines, and right-of-way corridors. HBB thrives in moist but not true wetland soils, and tolerates a wide range of soil moisture."

And here's the online iNaturalist description of this plant: "Rubus armeniacus, the Himalayan blackberry or Armenian blackberry, is a species of Rubus in the blackberry group Rubus subgenus Rubus series Discolores (P.J. Müll.) Focke. It is native to Armenia and Northern Iran, and widely naturalised elsewhere. Both its scientific name and origin have been the subject of much confusion, with much of the literature using one or the other of the two synonyms, and often mistakenly citing its origin as western European." Looks like the question of its origins is forever in contention and even knowledgeable sources and organizations will disagree on the matter.

Willamette Mission State Park is administered by the Oregon Department of Fish and Wildlife.

Sources:

Bennett, Max, "Managing Himalayan Blackberry in Western Oregon Riparian Areas," Extension Service, Oregon State University, 2006 (reprinted February 2007), 16pp., PDF copy, report, photographs, extended discussion, sources cited, accessed 11.5.15, http://pnw-ipc.org/docs/ManagingHimalayanBlackberry.pdf

"Controlling Himalayan Blackberry in the Pacific Northwest," Nature Conservancy, report, 3.30.04, 14pp., PDF copy, extended discussion and sources cited, photographs, accessed 11.5.15,
http://www.invasive.org/gist/moredocs/rubarm01.pdf

"Himalayan Blackberry," Washington Invasive Species Council, 2009, information page, added resource links provided, photographs, accessed 11.5.15, http://www.invasivespecies.wa.gov/priorities/himalayan_blackberry.shtml