If you live next to a highway, you probably hear a lot of noise from the road. A few ideas for creating a sound barrier between the highway and your back yard: Build a tall, solid wooden fence and plant vines on it - this will absorb sound. Soften up your hardscape - noise is probably bouncing off of your concrete and flagstone. Buffer your yard with plants - deciduous trees and broad leaf plants are the best sound-reflectors. Plant as densely as possible. You might also consider installing a water feature - it will add noise, but the sound of trickling water is soothing and might distract you from the highway noise.