13 Types of Mulch—and How to Choose the Right One for Your Yard

The right mulch will help your plants and trees stay healthy by retaining soil moisture and keeping their roots cooler in summer and warmer in winter. It can also make your life easier by discouraging weed growth. But there's a lot more to mulch than wood chips—there are actually several different types, made of all different materials.

Ultimately, almost any mulch type looks great in your landscape. "I like to use the analogy of painting a room," says Bob Mann with the National Association of Landscape Professionals. In the same way that a wall color can provide a neutral backdrop to showcase art and furnishings, the right mulch lets your flowers, shrubs, and trees shine, he says.

What Is Mulch?

Landscapers define mulch as any material placed over the surface of the soil as a covering. In addition to supporting plant health and keeping weeds down, mulch allows you to keep your mower away from trees, reducing the chance of an accidental injury to roots or trunks.

How Mulch Benefits Your Garden

Using mulch around trees and landscape plantings keeps grass from competing with them for resources. A good mulch layer also helps reduce the impact of raindrops on soil in your gardens and the landscaped areas around your house, says Aaron Steil, a horticulturist with Iowa State University Extension. With climate change increasing episodes of intense rainfall, that's becoming more important to manage.

Depending on the type you use, mulch can also improve your soil, making anything you grow in the your garden healthier and more beautiful.

What Is Mulch Made Of?

Mulch can be made of organic or inorganic materials—but you might notice a little crossover in the categories (for example, crushed seashells and sedimentary rocks contain organic materials but are usually in the inorganic category). As a general rule, organic mulches typically break down more quickly than inorganic ones. 

• Organic mulches, like wood chips, leaves, and other plant materials, are best at keeping soil moist and moderating its temperature in hot and cold weather. They also add some nutrients and improve soil structure and drainage as they break down. Organic mulches suppress, but don't block weeds.
  
  
• Inorganic mulches, like rock and gravel, can be a better choice in regions where fire is a hazard, but they tend to heat up quickly, which can harm plant and tree roots. Some, like plastic sheeting, block weeds but also prevent the infiltration of water and oxygen, killing the soil's microbiome—the community of living organisms that provide nutrients to plants and trees.
  
  And while inorganic mulches are often marketed as weed-free options, "it only takes one walk around the block to find a landscape with river rock or landscape fabric that has weeds growing on top of it," Steil says. "Over time, organic matter will build up on top of any mulch." 

Types of Organic and Inorganic Mulch

As mentioned, mulch can be made from many different materials—here are the most common organic and inorganic mulch options for your garden.

Organic Mulch Options

Shredded or Chipped Wood

Shredded or chipped wood enriches the soil as it breaks down, but the process is relatively slow—so you should get several years from an application before having to replace it. Shredded wood mulch, in particular, tends to interlock, making it less likely to wash or blow away than bark and chipped wood.

Before buying an inexpensive wood mulch, be aware that is often made from low-quality lumber or pallets and will break down more quickly, Steil says. It can also contain chemicals and dyes that can leach into your soil, which you'll especially want to avoid in vegetable gardens. By choosing a natural cypress or cedar mulch, which is naturally rot resistant, you can be relatively sure it's chemical- and dye-free. 

If you want to keep your wood mulch as earth friendly as possible, buy it from a local arborist or landscaper who chips trees and branches removed in your area, says Steil. Mulch produced this way will also be sold or delivered in bulk, eliminating the waste of plastic bags.

Wood Bark

Bark mulch can be especially good looking in the landscape. It tends to decompose more slowly than other wood mulches, which many homeowners like, but it can also be more prone than shredded or chipped mulch to wash away in a heavy rain. 

Shredded Leaves

While whole leaves mat down and can smother plants, shredded leaves allow air and water exchange and decompose more quickly, enriching soil and feeding plants while providing all the other benefits of an organic mulch. That makes them an excellent choice for vegetable gardens and around trees and shrubs.

You can buy or rent a leaf mulcher for shredding or simply mow your leaves with a lawn mower, using a mulching blade or mulching mower if you have a lot of leaves.

Leaf Mold

You can also partially compost your fallen, shredded leaves to create leaf mold. Popular with gardeners in the United Kingdom, leaf mold supports a healthy soil microbiome, which in turn can boost the nutrients and structure of garden soil, Steil notes. And while many gardeners believe composting has to be carefully monitored, "any pile of organic material will become a compost pile," he says—even one that's not enclosed in fencing or a purchased compost bin. 

Purists wait anywhere from six months to two years before using leaf mold, but you can start using yours as soon as it looks right to you, Steil says: "You don't have to let it get all the way to the point of looking like soil, especially if you're using it as a mulch."

Grass

Mown grass can be used as a mulch and is a great choice for vegetable gardens, where function typically overrides beauty. Apply clippings just 1 or 2 inches deep to keep them from overheating plants as they decompose. You can also partially compost grass clippings before applying them as mulch by making a pile, preferably at the back of your yard, since they might smell rich for a week or two.

Either way, avoid using clippings from recently treated grass as mulch in vegetable gardens. A good rule of thumb, Steil says: Wait until you've mown at least three times after applying herbicide or fertilizer.

Straw

If you love fresh-picked strawberries in spring, make straw your go-to winter mulch, as it will protect their dormant flower buds from extreme cold without smothering the plants. It's also good choice for protecting perennials, roses, and other tender plants in cold-winter regions.

Many garden centers and most farm supply stores have straw on hand year round. Avoid mold by choosing dry bales, and seek out organic straw for use in vegetable gardens. 

Cocoa Bean Shells

A by-product of chocolate production, cocoa hulls make a beautiful, deep brown mulch. They also smell amazing for the first few weeks after application. Cocoa bean shells are also a bit more expensive than other mulches. "I tend to use cocoa bean shells in highly visible or smaller areas, like a large annual container," Steil says.

Hazelnut Shells

The cracked hulls of hazelnut shells make a pretty amber mulch that looks great with complementary cool garden colors like violet and sage green. Hazelnut mulch is relatively expensive, but it also breaks down more slowly than other organic mulches, so you won't have to replace it as often. Because it is lightweight, it's better on flat surfaces, where it will be less likely to blow or wash away.

Pine Needles

Like straw, pine needles can be a great choice for strawberries and other plants that need winter protection because they won't pack down like leaves. And while they can make the soil a little more acidic, that's typically not an issue. "If you have some really finicky plants, you might consider it," Steil says. "But for most of us, pine needs aren't going to make a huge alteration of the soil pH."

Mushroom Compost

Mushroom compost is the mixture in which commercially farmed mushrooms are grown. It's typically a blend of materials, such as peat moss, ground corn cobs, crushed grapes from wineries, animal manure, hay, or straw, and is sold for general garden use after its nutrients have been reduced in the mushroom-growing process. 

While it won't build the soil as much as other organic composts, mushroom compost does provide some nutrition and performs the other functions of mulch, such as retaining moisture and tempering summer's heat and winter's cold. Be aware that it can also be high in soluble salts, which can harm seedlings.

Inorganic Mulch Options

Seashells

If you live near an ocean, you already know that crushed seashells can make beautiful garden paths. In a shaded area, where they're less likely to overheat, they can also work as a mulch. Mann, who lives on Cape Cod, cautions that in larger applications, the ocean scent of some seashell or oyster shell mulches can linger. 

Stone 

Volcanic rock, stone, and gravel offer visual interest in a landscape and won't hold moisture around drought-loving plants. They're best used sparingly and in shaded locations to minimize their risk over overheating plants and soil. Be aware, too, that when applied over plastic, gravel can kill soil microbiome and even shrubs and trees in your landscape by overheating their roots. 

Recycled Tumbled Glass

Available clear and in different colors, tumbled glass can make a pretty statement in a shaded garden and won't hold too much moisture around plants that like dry, rocky soil. It can also add visual interest when combined with other materials, especially when used sparingly in strips and smaller areas.

To keep it from working its way into the soil, you'll need to use landscape fabric, which can become clogged and restrict water filtration over time, or plastic, which can restrict water filtration and overheat soil.

How to Apply Mulch

Generally, you'll apply mulch 2 to 3 inches deep, with the exception of grass clippings, which you should keep to a depth of 1 to 2 inches.

Be sure to avoid building mulch "volcanos" against tree trunks and woody plant stems, Mann says, which can invite insects to bore into them, initiate infections, and even encourage root growth into the mulch. Instead, leave a few inches open around the base of trees, plants, and shrubs.

When to Apply Mulch

You can apply mulch almost any time, but avoid putting it down in early spring, which can keep cold soil cool longer and delay perennials from emerging. A new blanket of mulch applied in fall can temper extreme winter conditions, especially for new plantings and any perennials that are only marginally hardy where you live. Don't apply it too soon, though, or you might inadvertently slow your plants' process of going into dormancy, causing damage later. Head on over to our detailed guide on when to apply mulch for more information (and tips and tricks for mulching success).

"I always joke that you want to do it right before the mulch pile freezes," Steil says, "because of course, once it freezes, you're not going to be shoveling it anywhere." That's not easy to predict, he concedes, but the point is clear: Apply fall mulch as late in the season as possible. Rake it back in spring to allow the sun to warm the soil and reach emerging plants.