Description: The Himalayan blackberry is a perennial import from Eurasia that is an aggressive exotic which rapidly overtops the understory vegetation in the riparian forest, and spreads by extending long runners which root at the ends. A colony of blackberry can widen by 10 ft. or more a year, smothering every plant in its path. Huge areas of diverse riparian shrubs and forbs have been turned into low productive monocultures by this uninvited plant. The thorns of this species are large, woody arcs, like rose thorns, which draw blood easily. The leaves are in groups of three to five leaflets (usually five), and are much lighter in color on the underside than on top. Flowers are white to pinkish in color with petals 3/8 to 5/8 inch (10 to 15 mm) in length. Berries are blackberry-like, oblong and black in color. The canes are 5-angled, making large, stiff arches which can reach 10 ft. or more in height before bending over and traveling outward toward a new place to put down roots.
Distribution: Common, widespread throughout the Redding Field Office Area under 3400 feet (1036 m) in elevation, is most prominent in the Sacramento Valley portions.
Habitat: Frequently impenetrable bramble along rivers, streams, ditches, ponds, reservoirs, and other moist places from the Sacramento Valley into the coniferous forest.
Flowering Period: May to August
Similar Plants: There is a native blackberry species (Rubus ursinus - California blackberry) that sometimes grows along side its Himalayan cousin, is not aggressive and should be protected and encouraged. This native can be distinguished from the Himalayan species by: The thorns are small, straight prickles which are easily bent over by your finger. The leaves are three-leaflet groups exclusively, and are nearly the same color on the underside of the leaf as the top. The cains are round, green and flexible along the ground or climb weakly into low shrubs and return to ground level.