Natural edging for plantings
Trench edging looks great in informal garden settings. Use trench edging as a border around spreading evergreens or groundcovers or in areas where vinyl or other permanent landscape edging material would look too formal and unnatural. You can easily shift it if plants outgrow the bed. An open trench (Photo 1) holds back the adjacent grass better than a trench filled with mulch. But if you prefer a more finished look, fill it with mulch (Photo 2). You'll have to redig the trench once in a while to keep it neat and to hold back the lawn, but it doesn't take long and you can add the trimmings to your compost pile.
Wood chips, cocoa beans or cypress bark all work well for filling trenches.