Low maintenance landscaping: River rock, Rip rap, and Mulch

Offering reliable landscaping services to homeowners in British Columbia since 2013

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Sam Maerz

Owner/Foreman

Low maintenance landscaping is an ever-increasing design requirement to first improve the look and curb appeal of your home, and to do so with as little maintenance as possible.

As with every service-based industry who is doing the work and how is the key to successfully accomplishing the goal.

In this article we will discuss some material options, design considerations, mistakes that are typically made, and what ideas you can come up with based on local materials.

Low maintenance material options

River rock (round rock), Rip rap (angular rock), and Mulch are the most popular natural low maintenance material options. Using these 3 materials an unlimited number of designs can be created.

River rock or round rock comes from many sources including soil, rivers, and creek beds. Local quarries carry the most popular sizes 1-6”, while a nearby quarry in Squamish has a lot of custom options. A local stone supplier imports rocks and stones from all over North America and Mexico.

Choosing which rocks we can use in your project is entirely dependent on your budget, and ultimately how great your space will look.

 

Rip rap is angular stone of uniform size. Sizes are available from ¼” to several feet, although rip rap is a common term used to describe rock that is in the 3-12” range.

Because this stone is angular it stays in place better than round rock. Typically, this is used on slopes where retaining the soil is required.

Mulch is primarily made from wood materials although rubber options exist. Most landscape supply places have composted mulch, bark nugget, and playground chips.

Composted mulch is great for plants as the mulch has been broken down into a finer consistency. This looks like a chunky soil, but still fights off weeds.

The composted part of the mulch makes it a nice dark color when wet, and a dark brown color when dry.

Coloured mulch is my favorite as the mulch is larger in size (not as composted), and is a rich, vibrant, decorative mulch. The colourant is nontoxic to plants and animals, and looks black when wet or dry.

This mulch as it ages gets a very nice salt and pepper patina that I love.

Bark nugget is very chunky (2-4”) ground cover that is very unique. It adds color, and depth to a space that is very unique. Its readily available, although not used as frequently.

Playground chips are un-composted mulch that provides a full-size mulch product. Sizes of the chips usually range from ½”-3”. No soil like material will be in this mulch.

Certified playground chips are usually Whitewood, or Cedar. If being used in a playground the recommended depth is 9-12” after compaction (30%) to absorb falls from less than 12’.

Of importance to note playground chips are certified to be wheelchair accessible. Consider using playground chips in areas for walking paths, or where you may want to use a wheelbarrow.

These are the most popular readily available products in bulk. Specialty products of river rock, angular stone, and mulches are available in 40-50lb bags, but using them requires a small space to be cost effective.

Low maintenance design considerations

Low maintenance design considerations are project specific, and should be well thought out for what’s going to work best for your project.

River rocks should not be used in the highest elevation of your space.

River rocks by nature are smooth and round, and are not found high up. They are in the lowest areas where the water is. Higher elevations should be more angular rock that has not been smoothed by time due to lack of water.

River rock or round rock works really well in clean environments. Meaning I wouldn’t want to put rock around a messy tree.

Cleaning the tree debris is going to be difficult and high maintenance.

Putting rock around a tree will invite weed growth over time as the organic matter breaks down and forms soil in the layer of river rock.

When planting in river rock pay attention to the water requirements, and sun exposure. Rocks can quickly heat up and cook plants. Almost every rock garden needs irrigation, especially in full sun application.

When using river rock over a large space either break it up with plants, random mounds of rock, or with different colors of rock.

A flat sheet of river rock will not look as good as something with height, depth, and color variations.

Rip rap and angular rock size should match the space in good proportions. Go a little bigger than you think in terms of rock size, so you get good depth, but not by too much.

In areas where you can expect branches, twigs, and leaves to be on the ground use mulch. Preferably a darker color so as the debris decomposes it blends in and turns into the same product. White playground chips will almost immediately look dirty after a windstorm. They don’t match.

Modern mulches are dark in color, while red and orange mulches date the home usually to the 80’s-90’s. I remember as a kid we always had orange mulch. This is rarely popular in 2024. Rubber mulch in my opinion should never be used, due to its inability to break down.

It becomes dirt and full of debris at which point it ends up in a landfill vs. topping it off with new mulch.

Mulch preserves water and uses far less of it. If your budget doesn’t allow for built in irrigation than mulch will give you a fighting chance in keeping up with the irrigation requirements in the summer.

When making flower beds in a lawn, shape the beds so the lawn can be quickly mowed alongside of it. It will look more flowing, and function better.

Pro tip: Garden edging is rarely a good idea in my opinion. It’s not found in nature, and looks terrible. Its wavy and crooked either immediately or shortly after install. Instead plan for the finish height of the mulch bed to be slightly lower that the soil grade of the lawn.

The lawn being 3” high will act as the edge restraint should the mulch get moved around. This will create the lowest maintenance, best looking flower bed.

Mistakes that are typically made with low maintenance installations

 

Filter Fabric

The most common mistake we see is with the use of filter fabric. Knowing which type to use, and when.

There are two types of filter fabric Woven and Non-woven.

Woven filter fabric is a geotextile manufactured from polypropylene. Its primarily used to keep the earth from mixing with base gravel in a construction project. It has a high tensile strength and durability, but restricts water from moving through it. Its most notable recognized as having green strips spaced every 12”.

Landscapers unfortunately use this because its readily available at big box stores, and they don’t know the difference. It is not a weed barrier, it’s a water restrictor.

Underneath this fabric is a dry gravel layer 8’ deep.

Non-woven is a wool like fabric that has excellent water passing ability, and is a great filter fabric to use to separate soils from weeds. Plants thrive with it as it freely exchanges oxygen and water.

In a landscaping or drainage application only use non-woven filter fabric. Under a patio, driveway, or retaining wall the geotechnical engineer may spec woven geotextile fabric.

When should I use filter fabric?

Filter fabric is used to suppress weeds, and to keep a newly landscaped area free from grass and weeds growing in it.

Use filter fabric:  If the material is free from organic matter. I.E a river rock flower bed. This rock contains no fine material and nothing a weed could grow in. Place filter fabric on the ground, and then cover up with the rock. The filter fabric will block the soil below from growing a weed.

Use filter fabric: Under river rock, and clean clear gravel.

Non-woven filter fabric under this ¾” clear gravel

When not to use filter fabric:

Do not use filter fabric if the material you are using can grow a weed. I.E a mulched area can grow weeds when the mulch breaks down and forms soil.

If you have filter fabric under the mulch it will not prevent the weed from growing above it. Filter fabric in this case will not only be a waste of time and money it will cause you grief when it’s pulled up by accident when the area is re-mulched or worked in.

Do not use filter fabric: Under mulch, bark nugget, and gravels with fines (grey clay).

 

No fabric under the gravel or mulch

Excavation mistakes are made when a landscaper does not remove enough soil to make room for the new low maintenance space. This is always a cost cutting or lack of excavation equipment mistake.

For river rock excavate at least twice the depth of the rock being used. I.E for 4” river rock excavate down 8”. This ensures that at least two layers of rock are hiding the filter fabric and ground.

Any less than this and you will not get the depth perception that separate poor installations from great ones.

For Rip rap excavation follow the same rule of 2x the rock size for the depth, and increase excavation size at the foot of the slope. This will lock the rip rap from sliding down and constantly being a maintenance item.

Local material low maintenance design ideas

As you have read through this article and learned a little more about the specifics of low maintenance landscaping you have learned some basic principles, and some dos and don’ts.

The beautiful and I guess not so beautiful things about landscaping is its all subjective.

It’s an artform, and there are many ways to design, use, and appreciate a space. As you look at your project you may want to hire the design out, or tackles it yourself. Either way the local materials available, and your budget play a key role in what you can have done.

Start by visiting local landscape centers and seeing the rocks, mulch, and accessories in person.

The very best spaces are built over time following a theme whether that’s function, color, water, etc. Start with what you know and continue to build upon it over time.

If you would like to hire the design and build of your low maintenance landscape start by getting a quote today!