Determine which areas have drainage issues and identify the source of the problem. Is the soil line of your plant bed at least 4 to 6 inches above the rest of the ground? If the plant bed is based near the bottom of a slope, you may need to extend your edging beyond the plant bed to direct water runoff away from the plants.
Measure the perimeter of a landscaped area. The larger the area, the wider the edging should be to accommodate drainage needs.
Choose a material for your landscape edging that fits the colors and style of the rest of your landscape. Bricks, stones and landscape timbers are a few types of edging materials to choose from.
Dig a 12-inch deep trench along the perimeter of the plant bed. The trench should be wide enough to accommodate your edging material -- plus an additional 6 to 12 inches, depending on the extent of the drainage problem. Spread a 6-inch layer of sand or pea gravel evenly over the trench. This bottom layer will help absorb excess water and provide a stable foundation for the edging.
Press large, flat landscaping stones along the trench so the stones are partially underground. Wedge smaller rocks in the gaps between the large stones. Continue to work your way around the perimeter of the plant bed.
Lay a second layer of stones in the same manner, overlapping two stones beneath with the top stone for a more stable, layered look.
Fill in the rest of the trench with pea gravel, loose stones or other porous materials. Hide the gravel with soil or mulch if you prefer.