Some of us remember when the South Umpqua riverbank at Roseburg’s Stewart Park was covered in unsightly blackberry bushes. Its appearance in those days never would have elicited the kind of comments we hear from Music on the Half Shell performers. They marvel at the view of the river and the lushness of the grassy hillside amphitheater. Some remark on the sweetness of the plump wild blackberries that remain, but none has spoken of being heavily scratched by thorns while making their way to the water’s edge. Removing the briars there made a huge difference and now, a couple of …