Hello, An out of state investor bought a duplex for rental, and I'm working on a bid. Sprinklers, hydroseed, and 5 trees in a large lot. It is a weird deal in that it is off a gravel road. So the driveway is gravel, and goes right up the center of the property. So what will make a nice looking border to separate the gravel from the grass. Renters will be there, so they will drive on the border. Also, lots of snow in the winter, so the snowplow guys will drive into whatever I plant. Railroad ties are one option. Other options? Thanks!