In addition to this post from 2016, take note of a new post by Christopher Cheung in the Tyee about how blackberries took over BC.
Blackberries – delicious or dastardly? Many people love to pick this free fruit that grows in abundance from Vancouver Island to the Okanagan to Haida Gwaii. Blackberries are also considered to be a scourge; they’re prickly and invasive, creating impenetrable brambles and impossible to harvest without injuring oneself.
It’s interesting to note that there are at least three or more varieties of blackberries and they aren’t all invasive or prickly.
The Himalayan blackberry, Rubus armeniacus is the one everyone loves to hate. The Invasive Species Council of BC 
states that the Himalayan blackberry was introduced to BC in 1885. Its thickets are capable of producing 7,000 to 13,000 seeds per square meter that stay viable for several years. It competes with low-growing vegetation and can increase flooding and prevent the growth of larger species such as Garry Oak and ponderosa pine. Larger animals can’t get through the brambles. And don’t forget about the pain of picking! From blackberry rakes to a suit of armor, many people have tried to outwit the vicious blackberry barbs.
Two varieties of blackberries have much more redeeming value. The native blackberry, Rubus ursinus (trailing blackberry) grows well in many parts of the province and was extensively used by First Nations peoples for medicine, flavouring and teas. Crosses between trailing blackberries and raspberries have created some very popular cross berries – the loganberry, boysenberry and tayberry.
Thornless blackberries make picking enjoyable and productive. Most commercial growers are based in the Fraser Valley and blackberry growers claim that it’s possible to pick five pounds in fifteen minutes. Blackberries turn black well before they are ripe, and growers suggest waiting until the drupelets turn plump and fat for a sweeter berry.
What to do with all this abundance? Cobbler, crumble, clafouti, jam, jelly, juice, freeze some to put on your winter oatmeal porridge. I found a recipe for blackberry soup that I haven’t tried yet. Maybe I will, when it warms up in the Okanagan and my one thornless blackberry bush produces berries…
Update – August 24, 2020
See the following article by Christopher Cheung in the Tyee Online Newspaper: How Blackberries Took Over: The Unruly Colonizer
