Brick is sold by the piece and by the pallet. Used brick has been salvaged from sites/buildings undergoing redevelopment and is usually more expensive than new. Bricks vary widely in color but not in size; discounting the half-bricks used by masons to face concrete, dimensions are a pretty regular 4”x4”x8”.
Brick is fine for secondary paths, but since it tends to be slippery when wet I avoid its use in primary walkways or areas which are usually in some degree of shade (shade = damp = potential slip and fall).
Concrete pavers are brick-sized and multi-colored. I’m not crazy about them for anything but driveways — and even then with reservations — but they are incredibly durable. There are porous versions, and also some designed like sheets of mosaic tiles allowing grass to grow in and around them, softening the look.
Cobblestone is sold by the piece and by the pallet. There’s a wide range of available sizes and most stone yards carry them in three colors: gray, black and pink. They’re sized in jumbo (10”x7”x4”) and regular (9”x5”x4”) but many stone yards also carry a ‘landscapers’ size which corresponds to brick. These can act as visual breaks in a brick walk without changing the measurements, but also can act as a foot break by providing additional traction to guard against slipping. I use them with longer granite treads, both for the interesting visual mix as well as safety.
Granite treads are ordinarily used to top the risers on brick staircases or as hearth/mantle pieces, but they are terrific walkway material. They tend to be more expensive, but mixing them with cobblestone cuts the cost. Since they can be installed quickly, the cost of labor is reduced so I find that it’s pretty much a wash in budgeting the overall project. Although most granite is sold by the square foot, treads are usually priced by the linear foot; you may also, as I have, luck into pieces that the stone yard really wants to clear out, so don’t be afraid to ask if there’s a deal to be had!
Flagstone and slate are compositionally similar — both are sedimentary rock — and both can be had in regular or irregular shapes. Both also have a wide range of color; I’m a huge fan of lilac bluestone (a sandstone more in the purple range than blue) and a flagstone called chocolate gray, which mixes beautifully with the color range of New England granite. I do this because I prefer stonework to sit in a site rather than on it and a visual blend that mimics what is seen in the broader arena helps ensure that the built and unbuilt environments mesh.
Gravel comes in all shapes and sizes; peastone (so named for it’s size) is the most common for walkways, but I find that ¾” round has just the right ‘crunch’ to evoke walking along the stone beaches so common to Maine. Loose stone is sold by the ton; the supplier will be able to give you the approximate area covered by a 2″ or 3″ layer.
River jacks are the smooth, flattened, round stones you probably ‘skipped’ as a kid, although the ones for landscaping can be quite large. Smaller jacks are great for adding visual interest to walkways (they’re usually too expensive to be anything but top dressing) while the larger are perfect for adding drama or directionality to artistic stonework — areas meant for viewing rather than walking. While the smaller are most often sold by the ton, larger stones are sold either by the piece or pallet.
Groundcovers other than grass are used both for visual cohesion and weed control; those that are walkable include moss and creeping thyme. These wouldn’t survive in areas of heavy traffic, but for occasional use pathways they’re super.
Bark mulch: I’m not really a fan of mulching pathways, but use it liberally in the gardens and around trees. I like something commonly referred to as ‘dark bark’ for its shredded consistency and its color, since I don’t find the bark chunks to be as effective in weed control and the Day-Glo orange stuff is positively scary. Mulches, like compost, are sold by the bag or by the cubic yard (3’x3’x3′) meaning you’ll have to do a bit of math to figure out what you’ll need to cover at a 2″ to 4″ depth. Don’t go deeper than that, by the way; it won’t benefit the plants and just tends to go moldy. Mulch should not come in contact with the tree trunk; it rots the bark! Yes, I know you see it all over the place, but Master Gardeners everywhere will tell you it’s a no-no.
There are lots of other possibilities for use as mulch, including buckwheat hulls, pine needles and chocolate-scented whatevers, but for simplicity’s sake I prefer covers that blend into the scenery, stay where I put them and do their job. Primarily, that’s weed control, moisture control and erosion control. A secondary benefit can be an enhancement of acidity (in the case of pine needles or cedar chips) but I tend to use liquid applications of products like Miracid for specific plants and let the mulch simply be the mulch.
NB: I’ve seen a lot of homeowners using compost in place of mulch, but it seems to me that only provides a ready surface for weeds and doesn’t actually use the compost to advantage, which is the ‘leavening’ of the garden soil itself to give the roots of your plants the environment they need to be successful. Hate to use the trite adage of building a house on a good foundation, but in the case of both houses and plants, underground is where it’s at!