Stone Edging for Flower Beds: Options and Installation

The best stone edging for flower beds is stone heavy enough to stay put, set in a trench on a compacted crushed-stone base with a good part of each stone buried. Granite cobbles and edgers, bluestone strips, fieldstone and small boulders all work. What makes the difference in Massachusetts is the installation, because frost lifts edging that sits on loose soil.

Below are the main stone edging options for flower beds and garden borders, how they compare, and how to install edging stones so they stay straight and keep the grass out.

Stone edging options

Granite cobbles and edgers

Granite cobbles, often called Belgian block, and cut granite edging strips are the most durable choice. Granite does not mind freeze-thaw or road salt, and it gives a crisp, formal line. It is heavy, so it stays where it is set.

Bluestone edging

Bluestone strips set on edge, or flat pieces laid as a mowing strip, give a clean blue-gray line that matches bluestone walks and patios. Bluestone is a layered stone, so use thick, sound pieces; thin strips set on edge in wet soil can split along the layers over time.

Fieldstone and natural stone borders

Rounded fieldstone gives an informal, cottage-garden look and suits older New England homes. Stones dug up on site can often be reused. Sandstone edgers are another natural option, but quality varies, and softer pieces can flake in freeze-thaw.

Flagstone borders

Irregular flagstone laid flat along the bed edge makes a wide border that doubles as a path for a mower wheel. It suits curved beds and naturalistic gardens.

Boulder borders

A row of small boulders marks a large bed or the edge of a woodland planting with almost no upkeep. It is not a tight edge, so grass will grow between stones unless you trim it.

Concrete and faux stone block edging

Concrete edging blocks are uniform and easy to set in a straight line, and some have a stone texture. Faux and resin stone is light and easy to handle, but light edging is the type most likely to heave or shift. For edging that stays straight, heavier natural stone or concrete block is the better choice.

How the options compare

• Most durable: granite, then thick bluestone and fieldstone.
• Most formal: cut granite edgers, granite cobbles, bluestone strips.
• Most natural: fieldstone, boulders, irregular flagstone.
• Easiest to set straight: concrete edging block and granite cobbles.
• Best for mowing: a flat stone or cobble mowing strip set flush with the lawn.

How to install stone edging so it stays put

1. Call Dig Safe first. Even a shallow trench can hit a buried line near the house. Dig Safe requires 72 hours' notice in Massachusetts, not counting weekends and holidays.
2. Lay out the line. Use a garden hose for curves and a string line for straight runs. Look at it from the house and the street before you dig.
3. Dig the trench. Make it a few inches wider than the stone and deep enough for a base plus a good part of the stone below grade. The soil packed around the buried part is what holds the stone in line.
4. Add a crushed-stone base. Put in a layer of crushed stone, not pea gravel, which rolls and will not lock. Compact it with a hand tamper. A firm, draining base is what keeps frost from lifting the edging.
5. Set the stones. Set each stone tight to the next, tapping it down with a rubber mallet to the line and height. Check with a level or the string as you go.
6. Backfill both sides. Pack soil or crushed stone firmly against both sides and tamp it. Loose backfill is the most common reason edging leans.
7. For the strongest edge, granite cobbles can be set in a concrete bed with a sloped concrete haunch on the back side, the way granite curbing is often set.

Installing stone edging on a slope

On a gentle slope, keep the same buried depth along the run so the top of the edging follows the grade. On a steeper slope, step the trench: set each stone or short run level and step the next one down, like stairs. If the bed is holding back soil on the uphill side, the edging is acting as a small retaining wall. At that point it needs a deeper base and larger stones, and if it gets taller, a proper wall; see our post on building a retaining wall on a slope.

Keeping grass out of the bed

• Set stones tight together with no gaps for runners to slip through.
• Use a flat mowing strip, flush with the lawn, so the mower trims right to the edge.
• Add a vertical root barrier behind the stone where lawn grass spreads by runners.
• Re-cut the lawn edge with a half-moon edger in spring.

When edging becomes masonry work

Simple bed edging is a weekend project for most homeowners, and edging on its own is not a service Gerrior Masonry lists, so ask us whether it fits your project. Where it turns into masonry is when a bed needs a low wall, raised planting beds, steps between levels, or a border that is part of a walkway or patio. That is the work on our hardscaping services and retaining walls pages. For ideas on low walls around beds, see stone wall design ideas; for stone paths through a garden, see installing a stepping stone walkway.

"Your ideas and design work have transformed the “curb appeal” of our home, from the backyard & patio to the side planter wall and walk entrance." Tom and June, Stoneham, MA

Common questions

What is the best stone edging for flower beds?

Granite cobbles or granite edgers last longest and stay straightest. Fieldstone and boulders give a more natural look, and bluestone matches bluestone walks.

Why does my stone edging keep heaving?

It is usually sitting on soil with no drained base, or not buried deep enough. Reset it on compacted crushed stone with more of each stone below grade.

Do I need landscape fabric under stone edging?

It is not required. A compacted crushed-stone base does more for stability. Fabric can help keep soil from mixing into the base in wet areas.

Should stone edging be mortared?

Usually not for bed edging. Mortar joints crack when the ground moves with frost. A concrete bed and haunch under granite cobbles is the exception, and it needs a solid base.

If your garden needs more than edging, such as a low wall, raised beds or steps between levels, we can help. Gerrior Masonry is a family-owned company in Woburn, MA with over 30 years in masonry and hardscaping. We are fully insured, our work is guaranteed, and owner Joseph Gerrior oversees projects. Request a free estimate or call (781) 933-4157.