Make a gift in honor of the good that comes from BDN journalism in your hands, and help raise $60,000 this spring to support our reporting. Make a donation now. A multi-year project has started to eradicate invasive purple loosestrife encroaching on Walker Pond, a popular summer destination in the towns of Sedgwick and Brooksville. The plants flower in Maine starting in late July and produce millions of tiny seeds that travel easily and remain …