I didn't figure on the weedy things that would get into my new bed from the neighbor's yard, or the trouble it would be to trim messy looking long grass that pokes through the fence. - S. -
Fence lines are big trouble in gardens. Lawn, weeds and groundcover creep from one side to another. Seedling trees arise there, dropped by birds who perch on rails and wires above.
When we outlined this bed to turn a difficult incline into manageable terraces, it also gave us a place to stack and smother sod stripped to make other new beds. Before we started stacking, however, we trenched along the property lines to create a root barrier, so grass wouldn't creep in. When we do the next phase of work in this bed we'll replace that trench with a solid, below-grade barrier. We'll also reserve two feet along the fence for maintenance path, so we can keep an eye and a hoe trained on unwanted vegetation. We don't hide from the hard truth: that all the worst weeds begin on the edge.
Our diagram cuts the corner and highlights in violet the place where the greatest depth of new soil will be needed to cover a steep grade with plant-able terrace. Along the fence line, a root barrier's called for.
A trench bars creeper roots, for now. More about root barrier edging in What's Coming Up 51.
Sod lifted from areas of lawn made into garden are being recycled here. Turned upside down and covered, it will become "free" compost-soil mix.