Himalayan Blackberry
Himalayan blackberry (Rubus ulmifolius, syn: R. discolor)
Hawaii Pacific Weed Risk Assessment: 24 High Risk
Regulatory Status: None
Prevention and Control Category: OISC Target Species
Report this species if seen on Oahu
Description
- Spiny, woody bramble that grows as a sprawling bush, but may reach heights of 4 m (13 ft)
- White to pinkish flowers that become shiny black fruit when ripe
- Native to Western Europe, introduced as an ornamental and backyard food crop
Impacts
- Found in disturbed areas, open fields and around fresh water habitats
- Forms dense, impenetrable thickets that exclude other native plant species
- Seeds are spread by fruit-eating birds and mammals, also spreads vegetatively
- Thickets also make access difficult for hunters, hikers and other visitors to forest
- Infestations can produce 7,000-13,000 seeds per square meter, which can remain dormant in the soil for several years
Distribution
- Kauai: None known.
- Oahu: Known from only two areas on Oahu: Mauumae Trail and Palolo Valley in the southeastern corner of the island. OISC is working to eradicate these populations.
- Maui: Present at Waikamoi and Kaulalewelewe, West Maui, near the beginning of the trail to Puu Kukui.
- Molokai: None known.
- Lanai: Presence/absence unknown
- Kahoolawe: None known.
- Big Island: Present, but not currently a BIISC target. Landowners are encouraged to control where possible.