On an aesthetic level, "landscape" or "garden," or "lawn" edging (the terms are used more or less interchangeably) is a line of demarcation that creates visual interest in a landscape by separating one segment of your yard from another. But it may also be functional, as when you erect a barrier between a lawn and an adjacent flower bed to keep grass stolons from creeping into the latter. Read my tutorial (with pictures) to learn how to install such edging.
There are a number of different types of lawn edging. Maybe the most basic distinction we can make is that between lawn edging that consists of a trench versus the various types that form a barrier. That is, some landscapers create an edge simply by removing sod in a nice, even line to create the desired border, using a spade or a power edger. This might seem an easy way to install an edge, but the problem lies in maintaining it (you'll have to re-dig the trench).
That's one reason why most people prefer the barrier-style. But then the question becomes, What choices do you have for barrier-lawn edging materials and how do you decide between them?
Lawn Edging Materials
First of all, let's consider some natural materials. Natural stone is one of your possible choices. It's durable and looks great. But it can be expensive (unless you have some lying around in your landscape). It can also be relatively heavy -- a not unimportant factor for those whose health is not optimal.
Cobblestone pavers (granite setts) may be too cookie-cutter for those who crave an ultra-rustic look, but the flip side is that their uniformity makes them easier to fit neatly together.
Wood is another natural material that many folks find attractive. But untreated wood will rot quickly; that's why landscape timbers are treated with wood preservatives (which does, however, diminish this product as a "natural" option).
You can install landscape timber edging around flower beds. But due to health concerns over pressure-treated lumber, I would not use it around a vegetable garden. If you're concerned about lifting heavy objects, get someone to help with the installation of landscape timbers.
Then there are manufactured materials from which to choose. The four most frequently encountered are:
While metal lawn edging doesn't have too bad a name in the gardening community, many people despise plastic edging as being too cheap-looking. But plastic is also cheap cost-wise, so it is quite popular. Concrete is also popular (you're probably familiar with the reddish concrete blocks that have a scalloped edge), but with concrete, you run into the same issue as with natural stone that I mentioned above: namely, it can be heavy. Brick tends to be lighter and -- as a bonus -- is better-suited to a landscape design striving for a traditional look.
Then there are the more fanciful materials for lawn edging suitable for those whose primary concern is not practical in nature but rather to create a feel of whimsy in the landscape. I've encountered many examples of such materials in my travels, ranging from roofing tiles to the dishes you see in my picture.
If we get beyond the jargon and think outside the box, we will also recognize that there's some overlap between the subjects of lawn edging and raised beds. The typical raised bed is a shallow frame made of wood (the "edging" component) that is later filled with soil; then plants are installed in the soil. Thus the order of the steps in the project is simply reversed, as compared to the steps in installing edging (where the soil, and often the plants as well, are in place first; then the wood or other material is installed).
I provide instructions for creating a couple of atypical raised beds in the following tutorials:
See also: What Are "Edging Plants"?