Spreading mulch reminds me of raking leaves—-it’s an endless job when you’re in the middle of it, but the result is so gratifying. Mulch has tons of benefits—we’ll get to those—but probably the one homeowners appreciate the most is how it tidies up the garden. Who doesn’t love that clean, weedless, dark brown/black color with small, spring plants dotted about? It’s not July when the garden is overrun with weeds, plants, and humidity—right now, it’s in our control.

Mulch isn’t just decorative though, it is beneficial for the garden’s health. Here’s how.

Why Mulch? Because of Weeds (Mostly)

Mulch suppresses weeds. Before we get all happy about that, let’s qualify. Notice it says suppress, not get rid of. Mulch is one of the components in the weed war, and it doesn’t preclude you from pulling weeds in your beds, but a good pre-emergent and a 2” layer of mulch go a long way to reducing the weed population in your beds.

Weeds are competitors in the garden, drawing vital nutrients and water away from garden plants. Eliminating weeds isn’t the goal (read here for why some weeds are beneficial) but minimizing the competition and keeping the messiness in check is.

Mulching helps regulate soil temperatures in extreme bouts of heat and cold, and it helps to retain water during hot and dry seasons. Again, notice it helps. Mulch isn’t the cure, it’s the supplement. The gardener still has work to do, but mulch is hugely helpful in fighting against weeds and keeping plants hydrated.

And, as noted above, it is decorative. It can tidy up the place. As the garden coach, I’m frequently asked to help with curb appeal when folks sell their homes. Cleaning up beds and spreading mulch adds appeal quickly and is often all that’s needed.

What is Mulch?

Mulch is any material used to cover up the surface of a planting bed. It can be organic or inorganic. There are advantages and disadvantages to both.

Examples of Organic Mulches Include:

  • Shredded Bark

  • Pine Straw

  • Wood Chips (often dyed different colors)

  • Peat Moss

  • Groundcovers or living mulches

Examples of Inorganic Mulches Include:

  • Cobble Rock

  • Decorative Gravel

  • Pea Gravel

Pine straw mulch is more common in the south

Pine straw mulch is more common in the south

riverrockmulchsample-5994948

River rock mulch provides a much different look

Advantages of Organic Mulches:

  • Reduce soil moisture loss

  • Decomposition can add nutrients to the soil

  • Decomposition can alter soil pH

  • Benefits overall plant health

  • Moderates soil temperatures (hot or cold)

  • No mowing hazards

  • Discourage weed growth

Advantages of Inorganic Mulches:

  • Reduce soil moisture loss

  • No decomposition

  • Non-flammable

  • Rarely need replacement

  • Discourage weed growth

Disadvantages of Organic Mulches:

  • Potentially flammable in high heat conditions

  • Require replacement due to decomposition

  • Dyed mulches can get on clothing, animals, and paved areas

Disadvantages of Inorganic Mulches:

  • Does not affect soil pH, nutrients, or soil nutrition

  • Potential mowing hazard (can be thrown at people, windows, and cars)

  • May retain heat and harm plants in warmer areas

  • Children love to throw it into the yard

When to Mulch: Now, How to Mulch: Less is More

Example of improper mulching technique, which can lead to poor plant health or death

 

Example of improper mulching technique, which can lead to poor plant health or death

Mulch in late winter/early spring before the perennials show up, and covering beds is easier. You aren’t stepping on delicate perennial sprouts or covering them with mulch.

Two to three inches is the maximum amount to layer mulch—-two inches being optimal. More mulch isn’t the answer to your weeds and watering. Too much mulch can harm plants. See the picture? That is the WRONG way to mulch. Keep the mulch at least 3” away from the trunks of your plants because it can suffocate plants if it is too high up the trunk.

Piling up the mulch and then creating a well for water isn’t the solution either. Again, more is not beneficial and mulch is part of the solution, not the solution. You should see the root flair on your trees and shrubs at all times. Refer to the picture below.

Spread mulch using a pitchfork then rake it with a hard rake or spread evenly with your hands. Avoid piles in one place and not enough in another. Even distribution is what you’re going for.

tree-trunk-base-with-mulch-and-green-grass

Properly mulched tree base.

Groundcovers as Mulch

Sometimes it’s about planting, not spreading. Groundcovers can be ground-hugging or taller, like a hosta. Hostas are good weed suppressors with their large leaves and low-growing habits, so when you’re thinking about mulches, don’t forget the plants. Many plants are ground-covering plants that help keep weeds at bay and retain water. For more information on this, here’s a three-part blog on the use of groundcovers instead of traditional mulches.

Part One: Before Pictures of a Landscape Design

Part Two: Phase One of a Landscape Design

Part Three: After Pictures of a Landscape Design

Written by Cinthia Milner, Garden Coach, and blog writer.

B.B. Barns Garden Center serves all of Western North Carolina, upstate South Carolina, and Tennessee.