Lawn edging defines flower beds and lawns, keeping mulches and grasses in their proper place. The main types of edging include brick, stone, metal and plastic. Brick and stone cost the most, but are durable and add a decorative visual element to landscaping. Metal edging rusts, but lasts for 30 years. Plastic edging is the least expensive, but also the least durable. It tends to heave out of the ground during freezes. Grass grows up and around any edging, requiring trimming to maintain a neat look.
Place the back wheel of one side of the lawn mower on the edging, if the edging is less than 2 inches off the ground. Drive the lawn mower along the edging carefully so you don't send the mower into the flower bed.
Trim small areas with a hand-held trimmer. Pull the lever on the handle to open and shut the blades in a cutting action, as you carefully move along the edging until the entire area is trimmed. Trim the grass around the edging at the same height as the mowed lawn.
Trim larger areas with a gas or electric trimmer. Place the trimmer next to the grass and move along the edging, trimming the grass at the same length as the rest of the lawn. Be careful not to cut the grass too short, and avoid nicking trees.