How and Why to Mulch Your Plants

In nature, mulch is any fallen organic material that trees and shrubs naturally drop and, whether by design or by accident, improve their local soil environment for themselves. Composed of discarded leaves, shed bark and needles, small twigs, and anything else that might fall off a plant.

Adding arborist mulch can be a key factor that just may make or break your planting success! With so many applications and options out there, it can be difficult to choose the right mulch..

Read on about how to include this decorative and protective layer that acts like a nice snuggly protective blanket for your plant’s roots and the massive biome of life beneath your feet!

Why Use Mulch?

New and existing plants benefit greatly from a 3-4 inch deep layer of mulch over their roots. Sounds so simple doesn’t it? Almost too good to be true?

In reality, this protective layer acts like a shield between your roots and the harsh world above ground.

Mulch really can be anything that covers the soil. But why is it so highly recommended? Let us count the ways!

1. Mulch is an extra layer of protection from the elements, keeping moisture in the soil more regulated, slowing evaporation and erosion, and improving the quality and condition of your soil.
2. As the mulch decomposes, it improves fertility and aeration, aids drainage, loosens the soil, and prevents compaction.
3. With the incredible ability of moisture retention and preventing surface evaporation, you’ll save yourself time and heartache by preventing your investments from drying out faster in the heat, and less time spent watering! Creating more consistent moisture levels in the soil
4. Mulch also attracts beneficial insects and beneficial fungi to inhabit the ground and further improve the growing medium.
5. Mulch is also incredible at preventing and choking out weeds!
6. Creates a buffer zone between your plants and damage from lawn equipment.
7. Equalizing soil temperature is another benefit mulch brings to your landscape! Not only does it keep roots cool and hydrated in the sun’s heat, preventing the soil from becoming cracked and sun-baked. But, mulch also simultaneously insulates root systems from winter’s chill.
8. Not to mention the professional, manicured appearance that a layer of mulch provides your landscape! Mulch is an amazing buffer zone between your shrubs, planting beds, and borders from lawns and walkways. Creating a clean, weed-free zone and finishing touch to your landscape design!

Say No To Mulch Volcanoes!

Please avoid this common mistake when mulching! While arborist mulch is a fantastic protective layer, too much of a good thing is counter-productive.

Don’t create Mulch Volcanos by piling mulch up too high onto your shrub’s crowns and up against tree stems. Pull your mulch layer away from the plants a few inches to keep these tissues open to the air, keep insects from having a place to hide, and not hold moisture against above-ground stems and bark layers.

Always be careful about planting too deep and maintain your mulch layer to about 3-4 inches deep.

Types of Mulch

So what types of mulches are available to you and which application is best?

Wood and Bark Chips:

Most everyone is familiar with this type of mulch. Available about anywhere, even your local gas stations have it piled high in the summer. Comprised of either hardwood or softwood that has been chipped or shredded, or tree bark that has been shredded, this type of mulch is usually of the evergreen tree persuasion.

With a wide range of sizes and colors to choose from, wood and bark chips are low-cost and easily available. Available in many sizes, these size options are not just for aesthetics.

• Arborist Wood Chips are excellent and typically available for free. This shredded material typically contains wood, bark, twigs, and leaves all of varying size. The different rate of decomposition creates an environment that is more resistant to disturbance and supports a healthy plant population. Typically free through your city, and the most desirable choice.

• Cedar is a bit more expensive, longer-lasting, smells wonderful, and is a natural insect repellent. As does Pine and can aid in lowering your soil pH.

• Cypress, similar and less expensive than Cedar, smells wonderful and has bug-repellent properties. Cypress is usually lighter in color, but all these nowadays are dyed to a wide range of hues to match your design.

• Bark mulch is considered highly attractive. Holding its color well, and lasts longer before decomposing, bark mulch provides more aeration since the particles are larger. Air and water move freely around this great choice. 

• Wood chips are the chunkiest option available, large pieces and hunks are rough and coarse, but they last for a long time and are quite rugged.

• Shavings from woodworking and other craftsman leftovers are fine-textured and great to place around your informal garden beds.

Large chunks of bark do lend certain elements in landscape design, especially around larger plants that need that chunky presence, and they decompose slower and have a more long-lasting impact. 

Smaller pieces are of course finer texture in the landscape but need to be replenished more often. Shredded mulch provides an even, consistent look and lightens the feel of a garden bed. Plus are perfect for working around small branched plants or smaller, more delicate perennials.

Cons:

The other downside to bark mulch is that it does break down and will need to be replenished occasionally, depending on the size and type you use. Organic mulch materials do break down and you should maintain your mulch layer in the 3-4 inch range. Reapply as needed to keep your plants healthy.

Leaves and Needles:

For acid-loving planting beds, evergreen needles (also known as Pine Straw), which Pine trees shed yearly anyway, gradually break down and maintain acidity in the soil as they do. The smell is amazing, crisp, and clean too!

For more informal gardens and vegetable gardens, leaves and grass clippings are a highly cost-effective, and free option! Great at quickly breaking down and adding nutrients back into the soil each time you till and temporarily adding insulation. Mulching lawnmowers and bagging your lawn clippings make collecting this free resource easy!

Raking leaves from deciduous trees and adding them back to the soil closes the natural loop and keeps these free and rich amendments out of landfills. Top your beds and borders with loose, clean leaves for the winter, and fill cages around your Roses and other more delicate plants. Leaving the leaves in out-of-the-way areas also supports native pollinators and beneficial insects! Shredding the leaves with your lawnmower will keep them from matting. 

Cocoa Shells

For an amazing-smelling mulch option, you can always use Cocoa shell mulch, also called Cocoa bean mulch. Small and finely textured, these leftovers of the chocolate-making process are often discarded, but instead have been tapped as a fragrant mulch material! 

Cons:

The downside is that Cocoa mulch breaks down fast and, as I learned personally, can blow away quickly in strong winds. Also, there is concern that they are toxic if animals eat them. But their dark brown color, texture, and yummy smell are worth it in the right circumstances! Use Coco/Cocoa bean mulch in planters and areas near your entrance or patio where they are easily contained and you can appreciate the smell.

Straw and Hay Mulch

Straw and Hay mulch is often used on newly planted grass seed sites, around strawberry beds, and in the vegetable garden, but it’s also an inexpensive addition for a lighter mulching application. There are also rice hulls that are left over from processing rice that can be used.

Cons:

The downside is it breaks down much faster.

Compost & Yard Waste

Also known as black gold, is the fastest to break down and not the best to look at, however, is the pivotal addition to your culinary gardens and high-nutrient needy plants. The downside is sometimes the smell, the room that composting your own material takes, and again, possibly attracting critters. Compost can be incorporated into planting areas where you grow annuals and vegetables. Or you can use over the top of the soil in your landscape and then cover with arborist wood chips.

Other materials that do wonders but also contribute to recycling efforts include composting your kitchen waste, leaves, and yard trimmings. The use of these items is eco-friendly and keeps them from winding up in the trash heap. Instead, break down to improve your garden, block weeds, and keep the moisture levels consistent in the soil.

Just be sure the shredded paper products you use are without ink and the grass clippings and plant waste are without chemicals, especially if they’re going around your veggies and fruit! Also, be aware of any diseases or pests your leaves and clippings may harbor to prevent them from being reintroduced and spread around the garden.

Starting a compost pile of shredded garden and kitchen waste works just as well at acting as mulch and fertilizer too!

Cons:

These organic options mean less of a hit to the finances but require a bit more work each year. They will break down fast since compost is practically a short step away from being soil already and therefore will need to be replenished every year or so. Their benefits however are amazing!

More Permanent Options:

Lava rock, pea gravel, various stones, and even what you find on the beach are more permanent options available to gardeners!

Available in a wide range of sizes, shapes, and colors, and with no worry about breaking down in a few years, Rock and inorganic mulch is long-lasting and rarely needs to be refreshed. These options are many times used in commercial applications, walkways or pathways, or areas where plants are not being used.

• Pea gravel is a great fine-textured option for smaller xeriscape plants and rocks, gravel and even river rock suit larger plants greatly. Raking them back into place once a year and spreading them back out from time to time is all they really need.

• Lava rock and Pumice stone are lightweight options to stone, provide tiny micro-habitats for beneficial insects.

• Quartz Rock is the most beautiful, glistening, and sparkling in the sun.
• Chunks, crushed and decomposed Granite, and various sizes of River Rock also have amazing ornamental factors and are best used for walkways that can absorb water.
• Marble chips and flagstone are also available in some areas and provide a unique look to the landscape.
• Brick chips from construction waste liven up your planting beds and add a rustic look.

• Coastal areas benefit from crushed shell mulch, giving any planting site a beach feel. Sand is another fine-textured option available to those close to the source, and may even be free! Bring the beach to your front door with these unique alternatives!

Smaller textures are better suited around where you walk or play, around the patio, and for creating weed-free pathways. Larger sizes are for beds you won’t be walking through and to discourage animals like cats from digging in them and using them as their own personal litter box.

Cons:

The downside to these options is Rock mulch heats up in the sun and therefore may overheat root systems that need to be kept cool. Choosing lighter color stones to reflect the sun in hot climates is key. Alternatively, dark rock may cause lots of heating, thawing and then freezing at night and may not be great for plants. Or, abstain from using rock mulches for tender plants that would not be able to tolerate the hot dry microclimate that xeriscape plants can tolerate.

The downside to using larger rocks is that they won’t do well for smaller or delicate plants.

Weight and cost are the other downsides to Rock mulch, however, the longevity and boost to your home's value is worth it!

Rock mulches do not break down and do not need to be replenished, but they are best used for areas where plants are not being used. Sometimes even throwing off the pH of your soil, these options are not suitable for fruit and vegetable gardens.

Man-Made Materials:

Other long-lasting options with a wide range of applications are solid Rubber Bark mulch (or Pulverized Rubber), and other man-made materials. These are often recycled, further contributing to the environment! They are even available in premade sections for around trees, stepping 'stones', or in lengths for walkways; rubber mulch is versatile and easy to care for.

Rubber bark mulch is a great recycled material, made from shredded tires from cars and bikes that have been ground into various sizes. Often tinted into a wide range of color choices, these are amazing on paths, walkways, and playgrounds due to their bouncy, gentle texture. Great for walking on and blocking weeds amazingly, this option keeps the landfills free of reusable material. Falling on the rubber mulch won’t result in any skinned knees or elbows.

Cons:

The downside for rubber mulches is they easily wash out, absorb lots of heat, and could be a concern for chemicals leaching from these mulches. They are also a fire hazard so it may only be an option for around playground equipment. That does mean fewer skinned knees!

Landscape Fabrics

Using landscaping fabric beneath mulch used to be considered a great idea, however, recent studies concluded that Landscape fabrics are not effective weed control solutions for permanent landscapes. They will eventually cause maintenance problems in terms of appearance, weed control, and landscape plant health.

Cons:

Time-consuming and sometimes holding too much moisture are the only unfavorable factors with using landscaping fabric along with mulch. Strangle stems, smother roots, and break down fast. Any plant matter trapped beneath does not have any aeration and will rot. Good if you are trying to kill turf, but bad when pests, mold, mildew, and bacteria move in.

Does Mulch Color Affect Your Plants?

Black, reds, blondes, light browns, dark browns, there’s even pink, blue and yellow for the adventurous! You also have a wide range of colors to choose from to further enhance your curb appeal and match your garden design and style!

While the color itself doesn’t matter much, just be certain the dyes used are environmentally safe and non-toxic, so be sure to know the source and ingredients.

One study determined that black mulch may warm the soil faster by holding heat, and red mulch improved crops when used around vegetables and fruit.

Dye does fade and sometimes the chemicals that color it may even be harmful to pets or kids in large quantities. Not to mention potentially staining your hands, clothing, pet fur, or patio wood and rock if it’s not a regulated source. Sometimes it may be sourced from construction sites and demolition waste, full of imperfection, chemicals, and other cross-contamination.

Which Mulch Is Right For You?

Really, anything that has this many benefits to your soil quality, reduce heat stress, and plant health, should be at the top of your landscaping chore list!

With so many options available to you, it comes down to your own unique needs and your application purposes. Take into account budget, aesthetic, the plants you are mulching and your time available.

Once you determine the look and purpose, a layer of mulch everywhere in your landscape saves you time, boosts curb appeal, and adds that finishing touch to any planting site immensely!

Head over to the Nature Hills Nursery YouTube channel and watch as Ed Laivo, one of our resident horticulturalists, breaks it down for you! See what kind of mulch is right for several applications around your landscape. Learn about the proper depth for new plantings and as an annual topping here:

Happy Mulching!