by Connie Oswald Stofko A new border garden gives a South Buffalo backyard more privacy. The gardens at 222 Cumberland Ave. were on display Sunday, July 18 during the 10th annual South Buffalo Alive garden walk. Dave Testa, who lives in the corner property with Jack Tontillo, envisioned the kind of mixed border you might see at a big English house. “I hate the formality of straight lines,” he said, explaining the curved design he used. When choosing plants, “I…