Many people believe that black flies are the scourge of the Pacific Northwest. I’ve actually found that the blackberries are truly the biggest nuisance from my experience doing research in urban, suburban, and remote localities in Oregon and Washington.
Species: Himalayan blackberry (Rubus armeniacus Focke)
The Himalayan blackberry has been given many different species names, but it currently goes by Rubus armeniacus due to its Armenian origins (the most common taxonomic synonyms include R. discolor and R. procerus). There are a few different accounts on the origin of this pest, but the consensus seems to be that it was introduced first to Germany in 1835 where it is still cultivated, and it was introduced 50 years later to the United States by a botanist named Luther Burbank who gave it its current moniker thinking that it was originally from central Asia. Since then, it has escaped cultivation and spread to nearly half of all 50 states! This success is likely because the blackberry has evolved to grow rapidly, have thorns that deter browsing, and can colonize new areas clonally and by seed. Most importantly, it is a fantastic energy source for animals which eat the seed filled berries, involuntarily break down the coarse outer shell of the seeds in their stomachs, and deposit it–complete with fertilizer–when the seeds finally leave their system in a new location.
Map of states where Rubus armeniacus has invaded
Seasonality and Harvest
The invasive blackberry flowers in the late spring and early summer, and the fruiting season is at its height in the mid to late summers. The fruits can be identified as dark clusters of plump druplets (fruit with a fleshy outer part and stony seed in the middle) that are ripe when they can be plucked easily. They can be found in mesic habitats rubbing elbows amongst other deciduous species, particularly disturbed areas, on the sides of most roads, abandoned parking lots, and pretty much anywhere plants can grow and they are not actively removed. I collected some at St. Cloud State Park off of Highway 14 in Washington.
After harvesting to your fill, it would be exemplary of a true invasivore to destroy the patch from which you collected. However, as they can grow in areas prone to wildfires, please do not set them ablaze. Ultimately, the best form of control is prevention. Though the blackberry is already rampant in the United States, further spread can still be minimized. Pulling up seedlings, which can be identified as having light bright green leaves that are palmately compound with five leaflets, is a great way to prevent colonization. Prevention of secondary spread can also be achieved by being mindful of what berries you consume and where you choose to relieve yourself; so keep that in mind, and please avoid leaving digested seeds where they can grow into annoying blackberry bushes. If there is a large and brambly patch of blackberries you would like to remove, consider hiring a goat! There are many companies that rent out goats for landscaping and though most ungulates will shy away from the thorny canes, goats will eat them with fervor. Livestock for Landscapes is a great resource for finding a goat hiring agency in your area.