River rocks can serve many purposes from drainage to decoration in a landscape. A common feature in Japanese gardens, they are culled from actual rivers or sometimes from beach deposits. Different from other, sharper-edged gravels and pebbles, they have been worn and smoothed by moving water, colliding rocks, or the abrasive effect of sand.
But first, a disclosure: I am not a geologist, so I did some Googling as a starting point to learn about the many different sizes, colors, and ways to use river rocks in a hardscape. Are river rocks right for your garden? Read on for everything you need to know.
What garden designs look best with river rocks?
River rocks are popular in landscapes because they bring a naturalistic look to areas surrounding swimming pools, garden beds, trees, and water features.
What sizes of river rocks can I buy?
River rocks are available in a wide range of sizes, from very small (approximately 3/8 inches in diameter) to 5 inches.
Tip: Explore your local stone yard to get ideas and pick up samples to bring home. The colors are also variable, mainly earth tones, so they complement most existing color pallets. Also, because river rocks don’t break down (as mulch does) or need to be pruned (like ground covers), they are cost effective and a long-term solution.
What are the best ways to use river rocks in a landscape?
Let’s start at the top. The main reason people use river rocks is for creating water features, whether grouped around water fountains or used in waterfalls. Another main use is for building dry river beds, whether for the design aesthetics or to actually divert water away from the property and prevent erosion. Remember when building your river bed to incorporate various rock sizes to create a more natural look. Tip: Another field trip is to visit actual stream beds and see how Mother Nature builds them.
Less popular but still pleasing uses of the larger size river rocks are to create a natural edging and boundary for planting beds or lawns. For low-traffic areas, river rock can be an attractive ground cover substitute. While the large smoother pieces are difficult to walk on comfortably (and you should avoid running on them—I won’t go into the grisly details of why I know this), they have more permanence and a visual presence.
I admire when water-sensitive oak trees are underplanted with large river rocks, or when large maple trees with their dense, shallow, and challenging roots are decorated with river rocks.
Smaller river rock, sizes ranging from 3/4 inch to 1 inch, is suited for paths and walkways and their smooth texture makes them surprisingly pleasant to walk on.
And then there is Mexican beach river rock, also known as Mexican beach pebbles (as shown above). There are as many names as there are design ideas for this rock. Available in a natural dark finish and either a matte or a polished look, this versatile rock works as a final touch in containers, in a Zen-themed garden, and as a mulch substitute in a succulent bed.
How much do river rocks cost?
Typically sold by the pound or the ton, river rock costs can vary considerably depending on their size and where you live. Also, Mexican beach river rock is usually an expensive choice, so factor that into the design.
Are there any drawbacks to using river rocks in a landscape?
I won’t lie, weeding can be difficult with a large swath of river rocks because it is hard to get down to the weed’s roots without removing the rocks, so I recommend laying down landscaping fabric before installation. Also consider using a blower to make cleanup of leaves and debris less painful.
N.B.: For more of our favorite walkway and paver options see our Hardscape 101 guides: