You invite me over to pick em! Lived 30+ years in Ketchikan and found that heavy leather gloves allowed me to pull out much of the roots. It's hard, but you might find an ambitious high school student to hire to do that. Then mow close and pull out any starts, getting the roots.  Takes about three years. If they are growing wild just outside your lot, the roots will invade. If you are keeping some for eating, then it takes yearly (monthly) trimming, uprooting, etc to maintain salmonberries within whatever boundaries you want. We have an excellent receipe for "butterdips" (Bisquick baked in butter). Just add salmonberries on top while still hot. You get your entire daily calorie and vitamin C intake in one blissful meal. Sinful!