Don't Mulch with Rocks & What to Use Instead

Jul 28, 2026

In this controversial topic, we'll give you a few reasons why rocks do not make for a safe mulching option and which mulches may work better for you.

Our Hot Take: Don't Mulch with Rocks. Here's Why and What to Mulch with Instead

Rocks/gravel as mulch has become more common due to their aesthetically pleasing, simple, "clean" look in a garden. While rocks have their place in pathways or as borders, they are not the best "mulch" choice for surrounding your plants.

You may have seen examples of gravel foundations for xeriscape gardens*, but there's a misconception that this is the proper environment for these sorts of plants. Even for cacti gardens, think of natural desert soil. While very sandy, it doesn't consist solely of soley rocks. This could make the lives of desert plants even more stressful than they already are in such arid environments. Read below to find out why.

*Xeriscape Gardens- Gardens created to conserve water by using plants with low water consumption. Fun fact: roses can have a place in these gardens! See our collection of Earth-Kind Roses.

Potential Consequences of Using Rocks as Mulch

Rocks trap and reflect heat, making them your roses' worst nightmare during the summer. You may see your roses burning from all sides. This also applies to freezing temperatures.
Rocks do not make a good insulator, which would contribute to stress in extreme temperatures.

Rocks do not do your soil any favors in terms of aeration or microbiome contribution. Over a short period of time, rocks can compact soil. They provide no organic material to amend.

While rocks can initially solve the issue of weeding, even if landscape fabric is installed first, weed seeds will inevitably end up in your gravel bed. Pulling weeds from gravel, especially with tap roots, is very difficult.
- In many cases, gardeners might have to resort to chemical herbicides to prevent weeds in their gravel beds. Pre-emergents can harm your roses' long-term health, and broadleaf pesticides can directly damage them.

Some rock types can raise the soil pH, which is not ideal for roses, as they prefer a slightly more acidic soil than other plants.

A rock layer makes it difficult to adequately check soil moisture before watering.

What should I mulch with instead?

Shredded/Chipped Wood- Less likely to be displaced or washed away.
- Apply a layer of 2-3 inches, at least twice a year, or whenever your last layer has broken down to an inch.

Wood Bark- Decomposes more slowly, requiring less frequent application. Avoid treated or dyed barks.
- Apply a layer of 3-4 inches, at least twice a year, or whenever your last layer has broken down to an inch.

Shredded Leaves- Decomposes quickly and aerates compacted soil, but requires more frequent application.
- Apply a layer of 3-4 inches, at least twice a year, or whenever your last layer has broken down to an inch.

Leaf Mold- A potential DIY mulch option- composted leaves that take about six months until they're considered a "leaf mold". Apply when the leaves are not quite soil yet, or purchase at your local garden supply.
- Apply a layer of 2 inches, at least twice a year, or whenever your last layer has broken down to an inch.
- Great option for those looking to support their local insect population. Rather than throwing away raked leaves, pile them up somewhere.
  - Fun (actually depressing) Fact: the reason why firefly populations have been severely reduced is because of the obsession with "clean" yards and removing all debris such as sticks and leaves.
  - (Actual) Fun Fact: fireflies are not actually flies, but beetles! Explore our Lead Horticulturalist's hand-drawn Friends in the Gardens: Beneficial Insects Coloring Book.

Grass- Let dry out or compost a bit before applying to keep from smelling or overheating plants. If you've applied pesticide to grass, wait until after you've mowed 3-4 times before using clippings as mulch. Do not use if the grass has already gone to seed.
- Apply a layer of 1-2 inches whenever available.

Pine Straw- Easily accessible in pine forest areas. Pine straw is great for protecting plants from freezing temperatures. Great for soil moisture retention and preventing weeds from emerging from seed.
- Apply a layer of 3 inches whenever available.

PLEASE NOTE

Deciding to mulch with rocks will void your guarantee. A large portion of deceased roses in guarantee submissions we've received in the past have been roses surrounded by rocks or close to concrete, which causes the same complications.