Himalayan blackberry (Rubus armeniacus, formerly Rubus discolor and Rubus procerus) is a European shrub that was introduced in the United States as a crop in the late 19th century. It escaped cultivation and has since invaded a variety of sites, including low-elevation streamside areas throughout the Pacific Northwest. Listed as...
Yellow starthistle, a native of the Mediterranean region, arrived in this country in 1869 as a contaminant in alfalfa seed. It is a strong invader of disturbed areas, rangelands, and roadsides and thrives in areas of summer drought. A yellow starthistle invasion will reduce biodiversity by choking out native plants....
Published September 2008. Reviewed August 2014. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Scotch, French, Spanish, and Portuguese brooms were introduced into the western United States from Europe and the Mediterranean region in the mid- 1800s to stabilize mine tailings and other erosion and for landscaping. They now grow from western British Columbia to California (Figures 4a–d, following pages). The flowers had medicinal...
Gorse is a spiny, evergreen shrub native to the Mediterranean region. It was introduced on the West Coast of the United States as an ornamental in the late 1800s. Gorse was first found in Oregon in Benton County in 1916. Gorse infestations are concentrated along the Oregon coast, particularly south...
English ivy is a trailing or climbing vine in the ginseng family, native to Europe and brought to America by early colonists. It is commonly cultivated as a groundcover and is widespread in the Pacific Northwest, where it has invaded many wild and unmanaged areas. It is an aggressive invader...
Japanese and giant knotweeds were introduced to North America in the late 1800s as ornamentals but soon escaped into the wild. They are particularly invasive along streams, roadsides, and waste areas. Large, spreading patches of knotweed can completely dominate and displace native species in open sunlight. Erosion can increase on...
Knapweeds are a serious problem in Oregon because they vigorously invade disturbed or degraded sites and form dense populations that exclude native and desirable plant communities, causing economic and ecological losses. Their ability to spread rapidly by seeds and
roots makes control very difficult. Seeds can remain viable for 5...
Slender false-brome is a perennial grass species native to Europe, Asia, and North Africa. The species has exceptionally wide distribution, occupying forested and open areas at a variety of aspects and elevations. Populations are known in riparian forests as well as in upland hardwood and conifer forests under patchy and...
Published September 2008. Reviewed August 2014. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog