An Aggressive Neighbor

This is my neighbor's side yard; the side next to my house. You can see he is not into decorative gardening. What you do see is one of the most aggressive plants up here. It is called the Oregon Blackberry. But what is really is called is the Himalayan blackberry. Himalayan blackberry vines have invaded woodland areas of just about any space that will allow it to grow, which, as you can see, can be in a neighbor's side yard. The Himalayan blackberry is the most common blackberry species in the Pacific Northwest. Originally from India, it was brought to the United States from England--a pox on them, I say.
The rapidly spreading Himalayan blackberry is very aggressive, covering the ground and climbing high into branches of trees, creating walls of vines thickly armed with spines. Himalayan blackberry vines smother young plants, and can be seen surrounding just about anything that is stationary. If you have a lot, you have this blackberry. Even if you don't have this blackberry, you will, because the seeds are carried by bird droppings, and I know you have birds in your yard.
Removal is difficult, and requires cutting of the vines, and spraying of new leaves to kill the roots. We had a vine behind our storage area when we moved here in 2005. Very carefully, the vine was cut back to expose the base, and then the roots were dug up. We continue to monitor the spot, because these things just don't give up.
The only saving grace, if you would call it saving, is that in the summer, these vines are covered with hundreds of blackberries, which are sweet when they reach a dark black color. I find them a bit dry, and prefer the raspberries, but in a pinch they are a great food source. I just wish they were a food source next to someone else's yard.