Mulch is one of the best things you can do for your trees and shrubs—when applied correctly. It conserves moisture, moderates soil temperature, suppresses weeds, and adds organic matter as it breaks down. But too much mulch, or mulch applied incorrectly, can actually harm or kill your plants.
In Charlotte’s Piedmont climate, proper mulching technique is especially important. Our hot summers stress plants, and our clay soil benefits from the organic matter mulch provides. This guide covers exactly how much mulch to use and how to apply it for healthy trees and shrubs.
The Right Mulch Depth: 2-3 Inches
For most trees and shrubs in Charlotte landscapes, the ideal mulch depth is 2 to 3 inches. This depth provides the benefits of mulching without the problems of over-mulching:
- Moisture retention – Reduces water loss from soil evaporation
- Temperature moderation – Keeps roots cooler in summer, warmer in winter
- Weed suppression – Blocks light that weed seeds need to germinate
- Soil improvement – Adds organic matter as mulch decomposes
- Root protection – Cushions soil from compaction and mower damage
Mulch deeper than 3-4 inches creates problems: it holds too much moisture against bark, reduces oxygen to roots, and can harbor pests and diseases.
When measuring mulch depth, check the actual depth after settling—not the depth you just applied. Fresh mulch compresses significantly in the first few weeks. Add a bit extra initially to account for settling.
The Mulch Volcano: What NOT to Do
The most common mulching mistake we see in Charlotte is “volcano mulching”—piling mulch high against tree trunks in a cone shape. This looks tidy to some homeowners, but it’s actively harmful to trees.
Why volcano mulching damages trees:
- Moisture against bark causes rot and creates entry points for disease
- Hidden rodent damage – Mice and voles nest in deep mulch and chew bark
- Girdling roots – Roots grow into the mulch pile and wrap around the trunk
- Crown rot – Burying the root flare suffocates the critical transition zone
- Pest and disease habitat – Deep, moist mulch harbors harmful organisms
Volcano mulching kills trees slowly over several years. The tree may look fine initially while internal damage accumulates. By the time symptoms appear—sparse foliage, dieback, leaning—the damage is often irreversible.
Proper Mulching Technique for Trees
Step 1: Find the Root Flare
The root flare is where the trunk widens at the base and transitions into the root system. This area must remain visible and exposed to air—never buried under mulch or soil.
If you can’t see the root flare on your tree, carefully remove soil and old mulch until you expose it. Many trees are planted too deep from the nursery or have had mulch piled up over years.
Step 2: Create a Mulch Ring (Not a Volcano)
Apply mulch in a flat, donut-shaped ring around the tree:
- Keep mulch 3-6 inches away from the trunk
- Extend the ring outward as far as practical—ideally to the drip line
- Maintain 2-3 inch depth throughout the ring
- Leave the root flare exposed and visible
Mulch Ring Size Guidelines
The larger the mulched area, the more benefit your tree receives:
- Young trees (under 3″ trunk diameter): 3-4 foot diameter ring minimum
- Established trees (3-6″ trunk): 6-8 foot diameter ring
- Mature trees (over 6″ trunk): Extend toward the drip line as much as possible
Larger mulch rings protect more roots from mower damage and soil compaction, and provide greater moisture and temperature benefits.
A tree’s root system typically extends 2-3 times wider than its canopy spread. Most roots are in the top 12-18 inches of soil. The more of this root zone you can mulch, the healthier your tree will be.
Proper Mulching Technique for Shrubs
Shrubs follow similar principles to trees, with adjustments for their size and growth habit:
- Keep mulch 1-2 inches away from shrub stems
- Apply 2-3 inches deep throughout the bed
- Extend mulch to bed edges for a finished appearance
- Avoid burying low branches or ground-level foliage
Mulching Entire Beds vs. Individual Shrubs
For foundation plantings and shrub beds, mulch the entire bed rather than individual plants:
- Creates cleaner, more professional appearance
- Provides consistent moisture across the bed
- Reduces weeds more effectively
- Easier to maintain than individual rings
Best Mulch Types for Charlotte Landscapes
Not all mulches are equal. Here’s what works best in our Piedmont climate:
Recommended Mulches
Shredded hardwood bark – The most popular choice. Decomposes slowly, stays in place well, and adds organic matter. Look for double or triple-shredded for the best appearance.
Pine bark mulch – Slightly acidic, which works well for azaleas, camellias, and other acid-loving plants common in Charlotte landscapes. Available in nuggets or shredded.
Pine straw – Popular in the South, stays in place on slopes, and has a natural look. Slightly acidic. Needs refreshing more often than bark mulches.
Leaf mulch/compost – Excellent for soil improvement but decomposes quickly. Best used under a top layer of bark mulch.
Mulches to Avoid
Dyed mulches – The colorants don’t harm plants, but dyed mulch is often made from recycled wood that may contain contaminants. The bright colors also fade quickly and look artificial.
Fresh wood chips – Can temporarily rob nitrogen from soil as they decompose. Let chips age for several months before using, or use only on pathways.
Rubber mulch – Doesn’t decompose or add organic matter. Can release chemicals and gets extremely hot in summer sun. Not recommended for plant beds.
Buy mulch from reputable sources. Low-quality mulch may contain weed seeds, disease pathogens, or contaminants from recycled construction materials. Local tree companies often sell quality hardwood mulch from their chipping operations.
When and How Often to Mulch
Best Time to Apply Mulch
Spring (March-April): Ideal timing in Charlotte. Apply after soil warms slightly but before summer heat arrives. Mulch helps retain spring moisture through summer.
Fall (October-November): Second-best timing. Fall mulch protects roots through winter and is ready to provide benefits the following growing season.
Refreshing Existing Mulch
Most mulch beds in Charlotte need refreshing annually:
- Check depth – If existing mulch has decomposed below 2 inches, add more
- Don’t just pile on top – Rake and fluff existing mulch first
- Remove excess – If old mulch has built up too deep, remove some before adding fresh
- Watch the root flare – Each year’s addition can gradually bury tree bases
Calculating How Much Mulch You Need
Mulch is sold by the cubic yard. Here’s how to calculate your needs:
Formula: (Square feet × desired depth in inches) ÷ 324 = cubic yards needed
Quick reference for 3-inch depth:
- 100 sq ft = approximately 1 cubic yard
- 250 sq ft = approximately 2.5 cubic yards
- 500 sq ft = approximately 5 cubic yards
Bagged mulch conversion: A standard 2 cubic foot bag covers about 8 square feet at 3 inches deep. You’ll need about 13-14 bags per 100 square feet.
Bulk mulch delivery is usually more economical for areas over 200 square feet. Many landscape supply companies in the Charlotte area offer delivery by the cubic yard.
Common Mulching Questions
Should I remove old mulch before adding new?
Not necessarily. If existing mulch has decomposed and the total depth is under 3 inches, simply rake to fluff it and add fresh mulch on top. If buildup exceeds 4 inches, remove some before adding more.
Does mulch attract termites?
Mulch doesn’t attract termites, but it can provide habitat if termites are already present. Keep mulch 6-12 inches away from your home’s foundation, and don’t let it contact siding or framing.
Should I put landscape fabric under mulch?
We don’t recommend it for most plantings. Fabric blocks the organic matter benefits of decomposing mulch, restricts root growth, and eventually becomes visible as mulch thins. It’s useful for pathways but not around trees and shrubs.
Is it bad to mulch in summer?
You can mulch any time, but summer application is less ideal. Apply mulch to moist soil and water well after application. Avoid disturbing roots during heat stress if possible.
Professional Landscape Care
Proper mulching is just one part of keeping your trees and shrubs healthy. Our tree and shrub fertilization program ensures your ornamental plants get the nutrients they need, while our disease control and insect control services protect them from common Charlotte-area problems.
Healthy trees and shrubs—combined with proper mulching—create a landscape that looks great and requires less maintenance over time.
When we fertilize trees and shrubs, we check mulch depth and condition as part of our service. If your beds need attention, we’ll let you know. Get a free quote for our tree and shrub care program.