6 Mulch Options for Xeriscape Gardens
Planning a xeriscape garden but not sure what kind of mulch to use? Want to know more about the xeriscape philosophy and how to conserve soil moisture with mulch? In this article, certified master gardener Liz Jaros touches on xeriscape principles and offers seven mulch options for a water-conscious garden.
Contents
Whether planning a new landscape in a drought-prone region or interested in reducing your property’s environmental impact, you’ve probably heard the term xeriscape tossed about in certain garden forums. In simple terms, xeriscape is an approach to landscaping that minimizes supplemental water consumption and captures as much natural precipitation as possible.
Xeriscape Principles
Originally developed to address water shortages in the arid Southwest, xeriscaping is experiencing a rise in popularity due to its eco-conscious philosophy. It is fast becoming a gardening trend, if not a movement, all over the globe. Here’s a quick look at the primary principles of xeriscaping:
Reduce Water Use
The xeriscape movement’s top priority is reducing the need for supplemental watering and preventing evaporation. Although new plants will need extra irrigation for the first season or two while establishing roots, the ultimate goal is creating a landscape that generally sustains itself.
Depending on where you live, this means choosing drought-tolerant plants and designing a landscape that captures natural precipitation. When supplemental irrigation is necessary, use a soaker hose, rain barrel, or low sprinkler to direct water slowly at the earth rather than hastily at the air, where some will evaporate.
Always water in the early morning when possible to ensure that any moisture on plant tissue evaporates off in the sun, but consider soaker hoses at sunset to allow the plant the entire night to soak up the moisture. And, of course, using the rainwater you’ve captured reduces the need for piped water!
Improve the Soil
In regions where xeriscaping is commonplace, gardeners often deal with less-than-perfect soil. The first step toward creating an efficient landscape is amending the soil to be hospitable to plants and hold moisture at the desired level.
Soil that’s hard and dry during periods of drought but sticky and slow to drain during periods of precipitation is probably clay-heavy. Soil that’s loose and drains too freely might be sandy or lack organic material. Either way, the ground will likely need texture, drainage, and possibly pH level improvements before planting.
Use the Right Plants
A xeriscaped property features plants well-suited to the selected location’s climate, exposure, precipitation levels, and unique terrain. Choose trees, shrubs, and perennials that will thrive with limited human intervention once established.
This typically means choosing species native to a specific region or at least plants that are fully hardy in that zone. It may also mean choosing materials with root systems that discourage fast drainage or hold the soil in place.
Reduce Turf
Since traditional lawns require mowing, fertilizing, and regular irrigation to stay beautiful, a big part of the xeriscape movement involves reducing or eliminating turf grass. While this principle is not a strict, zero-lawn mandate, it does suggest you reduce the overall turf percentage and look for sustainable alternatives.
For example, to offset a small patch of grass kept by the house for kids or pets, a nearby gutter might direct roof water toward the area. Further back in the yard, you can replace the lawn with smaller plugs of perennial native grass, requiring significantly less irrigation and little maintenance. Consider the potential of alternative groundcover plants to maintain a low, no-mow profile, too.
Retain Water
Retain water to the greatest extent possible. This might mean installing boulders or retaining walls on sloped landscapes to slow rainwater’s natural pattern and prevent runoff. Plants with dense root networks can capture water as it passes by.
Ground insulation is also a top priority for xeriscapers. A thick layer of organic and/or inorganic mulch material will help keep plant roots cool, slow drainage, and discourage evaporation. It will also prevent soil compaction and provide an aesthetically pleasing finishing touch.
Xeriscape Mulch Options
The mulch that’s right for your particular property depends on your garden style, desired maintenance level, budget, and other factors. Here’s a look at the six most popular mulch options for xeriscape gardens and some of their pros and cons:
Hardwood
Wood chips, bark chips, cedar shavings, and sawdust are all organic mulch materials that can work in a xeriscape garden. Any of these wood-based products will decompose over time and add rich, organic material to the soil.
While the best bark mulch is arborist’s chips that contain woody and leafy green material from tree trimming, larger wood chips that lack the leafy component are a standard fixture in many gardens.
Pros
- Will break down and improve soil composition.
- Provides color, texture, and a finishing touch.
- Easy to install.
- Reasonably priced.
- Reduces weed pressures if applied in a 4-6″ deep layer.
- Degrades aesthetically over time.
Cons
- Decomposing hardwood consumes nitrogen from the soil within an inch or so of the wood, reducing availability to plants.
- Must be replaced every few years (much more frequently if it’s sawdust).
- May develop white fungal growth which some find unappealing even if it’s beneficial.
- Some bagged wood chips include weed suppressant additives and are not suitable for organic use.
Compost
Whether you’ve nurtured your stockpile from kitchen scraps and yard waste or purchased some from a local supplier, organic compost makes an excellent mulch layer for xeriscape gardens. Apply two to four inches on top of bare soil at the end of each season for an insulating layer that nourishes the soil below.
Pros
- Improves soil quality and texture.
- Has a neutral aesthetic.
- Easy to apply
- Inexpensive if you make your own (although time-consuming)
Cons
- Does not provide visual interest.
- If not fully broken down and cured, it can have an odor or may develop mold.
- Can be expensive to purchase.
- Must be refreshed/topped off every year.
Pine Straw
The go-to mulch for southern gardens, where large loblolly and longleaf pine populations create more than enough needles to go around, pine straw is also a popular xeriscape material. Pine straw is golden brown and gives off a light, woodsy scent. Applying a three to four-inch layer over unfinished soil can ensure this is a very effective and attractive mulch.
Despite persistent garden myths claiming it does, pine straw does not acidify the soil. However, it is commonly found in areas where the soil may already be acidic, as conifers often grow well in an acidic environment.
Pros
- Inexpensive.
- Lightweight and easy to apply.
- Attractive and natural looking.
- Adds nutrients to the soil.
Cons
- Might drift around in high winds.
- Must be replaced as it decays, usually topping it off annually.
- Not a great weed suppressor.
Leaves
Whether you run them through a mulching mower or rake them into a giant pile, fallen leaves are another organic material that insulates soil in a xeriscape garden. In a casual setting, leaves lightly cover exposed earth in the fall. In a more formal setting, gather and place them deliberately in certain sections to provide protection.
Pros
- Free if you have deciduous trees nearby.
- Very easy to install.
- Good weed suppressor.
- Leaves have a lot of nutrients and will improve the soil.
Cons
- Can look messy or uncared for.
- May blow around and collect in corners if left whole.
- If chopped, leaves rapidly decay and may not last more than 3-4 months.
- May be difficult to maintain even coverage.
Gravel/Rocks/Shells
Since the xeriscape movement originated in the Southwest, gravel, rocks, and shells are frequently featured in the overall scheme. While these materials can be included to provide structural interest and regional authenticity, a thick application of them can also be useful as mulch.
One of the most popular options in this category is lava rock or volcanic rock, which is slightly lighter in weight than pea gravel or other stones. Volcanic rock is relatively lightweight but remains in place well and can provide textural beauty to the landscape.
Pros
- Provide a tidy, natural aesthetic.
- Slow erosion and runoff.
- Provide interesting color and texture.
- May be gathered or found for free.
Cons
- Heavy and challenging to install.
- Will not decompose.
- May absorb and transfer heat to the soil.
- Difficult to weed.
- These can be sharp, uncomfortable, or hot to walk on while barefoot.
Rubber Scraps
Though not recommended for edible gardens or large applications due to potential toxicity and extreme heat retention, rubber scraps can be effectively used as xeriscape mulch in smaller settings. Rubber scraps recycled and processed for garden use will provide substantial moisture retention and weed suppression.
This option is not viable for people trying to stay organic, but if recycling in your ornamental garden is of interest, this may be a good fit for your needs.
Pros
- Tidy and easy to keep in place.
- Retains color for a very long time.
- Made from recycled material.
Cons
- Does not decompose or nourish the soil.
- Chemicals may leach and threaten sensitive plants.
- Retains heat and can burn bare feet in hot climates like deserts.
- Often expensive.
- May add microplastics to your yard.
Final Thoughts
Xeriscape is a garden philosophy focused primarily on water retention and conservation. The most inexpensive and effective way to keep garden soil moist is with a thick layer of mulch. Install the material that best suits your design style and water management plan, and you’ll be significantly closer to achieving your eco-conscious garden goals.
