Many gardening publications, including GHT, sing the virtues of raised beds. Warmer soil, earlier planting, richer soil--you've heard it all before. But have you heard about the biggest raised bed of all--a berm?
A berm is a mound or bank of soil without formal sides--kind of a big, relaxed, flowing raised bed. You often see enormous berms on the sides of highways, which is the transportation department's attempt at noise control. On a reduced scale, a natural berm can provide some interesting benefits in a backyard landscape, as well:
- Climate control. Berms act as windbreaks, channeling air flow. Berms can create a warmer microclimate or direct cooling breezes.
- Privacy. A berm can be a "friendly fence" in the back yard or between your house and a sidewalk.
- Vertical interest. You can add variety and texture to your gardens with berms, change the view from your outdoor sitting areas, or even hide eyesores with them.
- Noise control. A berm can cut down on traffic noise if you live on a busy street or near a schoolyard.
Berms aren't hard to make, but they take a lot of soil and you may need to have a contractor construct them for you. The critical factor in any berm is to keep the slope ratio at 3 to 2 (3 feet of width for every 2 feet in height). Berms may be shored with stone, bricks, or timbers, and planted with groundcovers, perennials, annuals, trees--you name it. Plants in a berm may also get a headstart on plants located elsewhere.