by Mark N. McCann
The Northwest’s ubiquitous Himalayan blackberry, Rubus procerus (AKA R. discolor), makes a safe haven for numerous bird species, rabbits and the Norwegian wharf rat. Residents of the Vancouver, Seattle, Portland and Eugene corridor can find few places this plant hasn’t colonized. Come fall, some residents will be found on roadsides collecting the dark berries in “double-dog-dare” fashion as tons of steel and glass go racing past. While the berries from this wide-ranging invader might make a reasonable preserve or jam, most species of native berries possess a far sweeter fruit. The down side is they produce far fewer berries.
A second species, the Evergreen or European blackberry, R. lacinatus, is less prevalent but is as unwelcome.
The five-leafed growth habit of the Himalayan blackberry is similar to some native berries, but the four-sided growth habit of the larger canes distinguishes it. Both introduced species produce four-sided canes, but the deeply incised leaves of the R. lacinatus are unique to the species. This blackberry’s vast range (all corners of the continent) has brought most of us into close proximity with this invader.
Introduced berries form large dense thickets as impenetrable as concertina wire several meters tall, with few exceptions, it is the only species with thorns that is evergreen. The bulk of native berries within the corridor are, in fact, deciduous.
Due to its two-pronged ability to reproduce both vegetatively and by fauna cast seeds, (animals eat the berry and ... well, you know), this invader has spread throughout the countryside, however, even the fauna cast seeds have a limited range. This is why most briar patches will be found near present or former settled sites.
Keeping the berries and animals that feed on them at bay can keep the plant contained, but with the first cast seed, the invasion begins. The result is alarming.
The methods touted by professionals cover the gamut of solutions, ranging from civil engineering projects to rampaging herds of genetically altered Über goats. This species seem to be unaffected by most poisons (at least those that don’t glow in the dark), while the labor intensive method of pulling out the root ball is the one proven technique to rid an area of this ultimate survivor. Spraying with poison will kill the above ground portion of the plant while the seeds and root ball remain in some kind of stasis awaiting spring and another dose of “liquid death” squared (liquid death2). Those not keen on chemically induced brain damage will find the root ball comes out easily when the ground is still wet, but remain on guard, because after the mother plant is removed the seeds will begin to grow in the newly exposed soil. After a couple of seasons of removal, they should not return.
Mowing these plants can keep them from spreading, but be prepared to do this several times a year. Mowing after the flowers appear can keep the plants from fruiting and then showing up in your neighbor’s yard. Like all species labeled “non-native invasive species,” they spread easily and don’t respect property lines.
Blackcap berries (Rubus leucodermis), the tastiest of the corridor’s berries, are easily distinguished by its upright growth habit and round gray-green stems.
Salmonberry (R. spectabilis), a wide spread native, may not produce the tastiest berry, but localized patches can produce better tasting fruit than others. A word of caution when harvesting this species: the thorns of the salmonberry are deceptively small. The thorns break off at the slightest touch and will fester days later in an unpleasant itching. Salmonberry is often found in pure drifts, indicating it may possess some alleopathic (a self-produced systemic poison that keeps competing species at bay) quality.
Trailing dewberry (R. ursinus), a ground hugging native berry, has a delightful tasting fruit, but this native is the most tripped over plant found in the corridor. The tendrils from the ursinus (the Latin root word, ursa, means “bear”) enmesh into the surrounding flora, creating an obstacle worthy of an NFL training camp. However, the thorns of the dewberry warrant the species name of “bear.” They can penetrate most gloves short of rhino hide. The species is dioecious (requires male and female plants to produce fruit), and it is common to see large patches of barren male plants.
Red raspberry (R. ideaus) is a species found more often on the dry side of the Cascades. It produces a great berry and can produce large quantities of fruit if cared for.
All the above species do provide forage for birds and many species of animals. Additionally, the snowberry (Symphoricarpos albus) retains a long lasting waxy white berry that is attractive to many native species of birds and animals throughout the winter months, but it is poisonous to humans.
Mark N. McCann is currently working on a book about Green Space and Stream Stewardship within the Vancouver-Seattle-Portland-Eugene (VSPE) Corridor. Based on his five years of experience removing invasive species, and replanting and propagating natives species within the Tryon Creek State Natural Area (TCSNA) as a member of the Adopt-A-Plot program. He has been a Citizen Member of the Tryon Creek Watershed Council, Friends of Tryon Creek and presently is a volunteer at Berry Botanic Garden, specifically in the Native Plant’s Trail and in the Propagation Department.
Photograph by Debbie Teashon