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Have you seen Himalayan blackberry (Rubus armeniacus)?
Hawaii Early Detection Network Priority Pest for the islands of Oahu, Kauai, Molokai, and Lanai

Rubus discolor leaf
Himalayan blackberry leaves have 3-5 leaflets
Image: © Barry Brecckling
Rubus discolor
Flowers with 5 petals
Image: Forest & Kim Starr
Rubus discolor flower
Older Himalayan blackberry stems are strongly angled with stout prickles Image: © Zoya Akulova

Identification: Himalayan blackberry, which is native to Western Europe, has become a pest in many of the temperate regions of the world where it has been introduced. It is a rambling bush with thorned canes that grow into 10ft tall in dense mounds. The leaves are palmately compund and commonly have 5 leaflets that are round to oblong with a ttothed edge and have hooked prickles on the leaflet stems (petioles). Leaflets are light greenish grey below. The canes are noticeably angled in a star-like shape and often have a reddish color and appear to be covered in a whitish dust. It has white flowers that are 3/4 - 1 in long. The berry that forms is black and shiny and 3/4 in long.
Impacts: This blackberry can form impenetrable thickets with up to 525 prickly canes per square meter. It thrives in wet areas, though it can establish in open, disturbed areas, pastures, and forests. It can make access difficult for hikers, hunters, farmers, and any others that wish to cross its path.
Dispersal Mechanism: It is eaten and spread long distances by a varity of birds and mammals. Infestations can produce 7,000 to 13,000 seeds per square meter, where the seeds can remain viable for years. It can also spread vegetatively, through root suckers and aerial rooting. This plant is widespread throughout the state of Hawaii, except for on the islands of Oahu, Kauai, Molokai, and Lanai. If you see this plant anywhere on these islands, let someone know!

More information about this pest external link

Himalayan blackberry look-alikes:

Florida prickly blackberry (Rubus argutus):
Florida prickly blackberry a widespread non-native blackberry/blackberry found throughout Hawaii. This blackberry has five petal WHITE FLOWERS with petals 13-20 mm long. The fruits turn BLACK at maturity and are 1.5-2 cm long. It can be differentiated from Himalayan blackberry by its leaves, which are skinnier and have


Rubus argutus

Blackberry (Rubus argutus)

Akala (Rubus hawaiiensis):
The native Hawaiian blackberry can be distinguished by its pale prickle covered stalks and PINK FLOWERS. Akala is the only blackberry/blackberry that loses its leaves in the winter.

Rubus hawaiiensis

Akala (Rubus hawaiiensis)

Last Updated: Thursday January 10 2013. If you have any questions about the Hawaii Early Detection Network contact
Funding and support for this project was made possible by the Hawai'i Invasive Species Council, the USDA Forest Service State and Private Forestry assistance, and University of Hawai'i-Pacific Cooperative Studies Unit.