Roots and Shoots: Getting the Edge

Edging, or material used to create a boundary, can become as much a design feature in a garden as the plants. Or it can disappear, such as into foliage. I’ve used many types over the years and still haven’t developed any hard rules for when and where. 

Edging can break the flow of grass, perennials or shrubs. As a border, it can speak to cultivated areas or form a transition between cultivated and uncultivated, communicating intention. 

In functional terms, edging keeps one type of plant from encroaching into the space of another. For example, it can prevent lawn grass from moving into a flowerbed or keep the mint from escaping into the lawn. It also works to keep soil and mulch from shifting into the lawn during rainstorms or when you’re raking. 

I prefer stone, wood or metal edging instead of plastic for sustainability reasons and also because they are easier to work with. Plastic edging comes in rolls and, unless you need a lot of curves, can be unwieldy and bulky. That said, it is the most affordable option and can be installed without any expertise beyond what you learn from the package instructions. The only tools required are a shovel and hammer to pound the spikes that hold it in place. (Be sure to use the spikes or the plastic will be pushed out of the ground in the winter during the freeze-and-thaw cycle.) 

Recycled plastic or recycled rubber are a bit more expensive, although don’t be fooled: Their carbon footprint may still be higher than wood or stone. I’ve found rubber edging can become a problem for weeding; at one garden I visited, the weeds had grown through the matting and it had to be removed. 

Lately, I’ve been working with steel edging, which is available in heights of 4 to 8 inches. It’s easy to install without digging a trench; it slips into the space. It’s also attractive and can be bought with a rust patina or will acquire one. It will last for a long time. 

Stone, rock, bricks and pavers offer a classic look or a cottage feel and do not wear out or decompose. The most common options are limestone or sandstone, with a pale hue. Installation is labor intensive, however, and a workout for your back. You’ll need to dig a trench and add a layer of leveling sand. 

After tamping the sand down so it won’t settle, each stone has to leveled. It takes more tools and time than pounding in sections of metal. 

In my home landscape, I use whatever I find. Natural materials are abundant and it feels good to repurpose them, including logs, branches and rocks. After having a tree taken down, I asked the team to cut the largest trunk pieces into 6-inch rounds. These became the edging for a flowerbed I created near where the tree stood. Ten years later, the rounds are less solid but that’s just an opportunity to develop a new look! 

If you’re going for quirky or artistic, I’ve seen edging made with upended wine bottles, woven willow and wrought iron shaped into patterns. But I’m not sure about how functional those options are in the long term. Edging has to extend at least a few inches into the ground to make a barrier that can block grass from invading a flowerbed.