Recently a friend asked if I had any suggestions for creating a sound barrier in front of his house. My first idea was arborvitae. These neat symmetrical conifers are popular because they are not only handsome, but because they are low maintenance plants. They are hardy, not fussy about soil, are fairly salt tolerant and once they are established they are drought tolerant. They also tolerate some shade but need at least four hours of sun. Two easily…