Bark Mulch vs Wood Chips vs Gravel: Comparing Mulch Types

Choosing the right mulch can transform your garden’s appearance while improving soil health. But with bark mulch, wood chips, and gravel all readily available, how do you decide which is best for your needs?

In this guide, I’ll compare these three popular mulching materials across all the factors that matter – appearance, cost, longevity, soil benefits, and practical considerations – to help you make the right choice for your garden.

Quick Comparison Table

Bark Mulch: Natural and Soil-Enriching

What Is Bark Mulch?

Bark mulch is made from the outer bark of trees (typically pine, cedar, or hardwoods), shredded or chipped into pieces ranging from fine nuggets to larger chunks.

Advantages of Bark Mulch

• Improves soil structure: Breaks down gradually, adding organic matter
• Excellent moisture retention: Keeps soil consistently moist, reducing watering needs
• Natural appearance: Provides a neat, professional look in ornamental beds
• Weed suppression: A 7-10cm layer effectively blocks light and prevents weed germination, particularly effective against weeds like dandelions
• Temperature regulation: Insulates soil, keeping roots cooler in summer and warmer in winter
• Pleasant smell: Fresh bark (especially cedar) has a natural, woody fragrance
• Variety: Available in different sizes, grades, and sometimes colors

Disadvantages of Bark Mulch

• Needs replacing: Breaks down over 2-3 years, requiring replenishment
• Can blow away: Fine grades may scatter in windy exposed locations
• Can attract slugs: Moist environment under bark provides ideal slug habitat (see our guide on managing slugs in mulch)
• Nitrogen tie-up: Fresh bark can temporarily reduce nitrogen availability as it decomposes (use well-aged bark)
• Variable quality: Cheap bark may contain wood pieces or decompose too quickly

Best Uses for Bark Mulch

• Ornamental flower beds
• Around shrubs and trees
• Rose beds (provides ideal moisture and feeding environment when mulching roses properly)
• Woodland gardens
• Front garden borders (for curb appeal)

Cost

• UK: £4-7 per 70-litre bag; £40-60 per cubic metre in bulk
• US: $3-5 per 2 cubic feet bag; $25-40 per cubic yard in bulk

Wood Chips: Budget-Friendly and Long-Lasting

What Are Wood Chips?

Wood chips are made from whole branches and small trees, chipped into irregular pieces. They include both bark and wood, creating a more varied, chunky appearance than pure bark mulch.

Advantages of Wood Chips

• Cost-effective: Often the cheapest organic mulch option
• Long-lasting: Takes 3-5 years to fully break down
• Sometimes free: Tree surgeons often give away fresh chips (use aged chips for best results)
• Good soil improvement: Adds organic matter as it decomposes
• Excellent for paths: Compacts slightly, creating stable walking surfaces
• Rustic appearance: Natural, informal look suits cottage gardens and woodland settings
• Won’t blow away: Larger, heavier pieces stay put in wind

Disadvantages of Wood Chips

• Nitrogen depletion: Fresh wood chips can tie up nitrogen during decomposition (always use aged chips, or add nitrogen fertilizer)
• Less refined appearance: Chunky texture doesn’t suit formal gardens
• Variable quality: Free tree surgeon chips may contain unwanted species or large pieces
• Can harbor pests: May attract termites near wooden structures (though this is rare in UK)
• Initial heat generation: Very fresh chips can generate heat as they begin decomposing

Best Uses for Wood Chips

• Garden paths and walkways
• Large informal areas
• Woodland gardens
• Around established trees and hedges
• Play areas (use certified playground-grade chips)
• Back garden utility areas

Cost

• UK: £3-5 per 70-litre bag; £25-40 per cubic metre in bulk; FREE from tree surgeons
• US: $2-4 per 2 cubic feet bag; $15-30 per cubic yard in bulk; FREE from arborists

Gravel: Low-Maintenance and Permanent

What Is Gravel Mulch?

Gravel encompasses various stone materials including pea gravel, crushed rock, decorative aggregates, and slate chippings. Sizes range from fine (6mm) to coarse (20mm+).

Advantages of Gravel

• Permanent: Doesn’t break down or need replacing (10+ year lifespan)
• Low maintenance: No topping up required
• Excellent drainage: Perfect for Mediterranean plants and areas prone to waterlogging
• No slug habitat: Dry, inhospitable environment for slugs and snails
• Formal appearance: Clean, tidy look suits contemporary and Mediterranean gardens
• Color variety: Available in many colors to complement planting schemes
• Deters cats: Uncomfortable surface discourages use as a litter tray
• Fire-resistant: Safe choice near fire pits or BBQ areas

Disadvantages of Gravel

• High initial cost: Most expensive mulch option upfront
• No soil improvement: Doesn’t add organic matter or nutrients
• Difficult to remove: Hard to change if you want to alter the garden later
• Mixes with soil: Over time, gravel works into the soil, making cultivation difficult
• Weeding challenges: Weeds growing through gravel are harder to remove than from organic mulches – particularly problematic weeds like horsetail or ground elder
• Heat reflection: Can increase temperatures around plants in hot climates
• Requires membrane: Needs landscape fabric underneath for effective weed control
• Can be noisy: Crunchy underfoot (though some see this as a security benefit)

Best Uses for Gravel

• Mediterranean and drought-tolerant plantings
• Contemporary and minimalist gardens
• Driveways and parking areas
• Around succulents, alpines, and lavender
• Japanese-style gardens
• Low-maintenance front gardens
• Shaded areas where organic mulches might develop fungus or smell problems

Cost

• UK: £60-150 per tonne (covers approximately 10-12m² at 5cm depth)
• US: $40-100 per ton (covers approximately 100 sq ft at 2″ depth)
• Plus: Landscape fabric (£0.50-2 per m² / $0.10-0.50 per sq ft)

Head-to-Head Comparison by Garden Type

For Flower Beds

Winner: Bark Mulch

• Improves soil as it breaks down
• Natural appearance complements plants
• Easy to work around when planting new additions
• Retains moisture for thirsty flowering plants

For Paths and Walkways

Winner: Wood Chips

• Most affordable option for large areas
• Creates stable, comfortable walking surface
• Natural appearance suits informal gardens
• Gravel is good alternative for formal paths

For Low-Maintenance Areas

Winner: Gravel

• No replenishment needed
• Permanent solution
• Clean, tidy appearance year-round
• Best long-term value despite higher initial cost

For Vegetable Gardens

Winner: Neither – use dedicated vegetable garden mulches

• Instead, consider straw mulch, grass clippings, or compost
• These materials add nutrients vegetables need
• Easy to dig in at season end
• Wood-based mulches can tie up nitrogen that vegetables need

For Shrub Borders

Winner: Bark Mulch or Wood Chips

• Both provide excellent soil improvement
• Choose bark for visible front garden borders
• Choose wood chips for larger, informal areas to save money

Can You Mix Different Mulch Types?

Yes, and sometimes this works well:

• Gravel + bark: Use bark in planting beds, gravel for paths – creates visual distinction
• Wood chips + bark: Wood chips as base layer (cheaper), topped with decorative bark
• Avoid: Don’t mix gravel with organic mulches – makes both difficult to manage later

Environmental Considerations

• Bark mulch: Renewable if sourced from sustainable forestry; choose FSC-certified products
• Wood chips: Often a byproduct of tree surgery (waste utilization); very sustainable
• Gravel: Non-renewable resource; quarrying has environmental impact; very long lifespan reduces replacement needs

Final Recommendation

There’s no single “best” mulch – it depends on your specific needs:

Choose bark mulch if you want:

• The best soil improvement
• A neat, professional appearance
• Traditional ornamental garden aesthetic
• Maximum moisture retention

Choose wood chips if you want:

• The most budget-friendly option
• Long-lasting coverage for large areas
• Natural, informal appearance
• Effective path or woodland garden mulch

Choose gravel if you want:

• A permanent, low-maintenance solution
• Contemporary or Mediterranean aesthetic
• Excellent drainage
• Best long-term value (despite higher initial cost)

For most traditional UK gardens, I recommend bark mulch for ornamental beds and borders, wood chips for paths and large informal areas, and gravel for drought-tolerant plantings or low-maintenance zones. Before making your final decision, remember to calculate how much mulch you’ll need to avoid over or under-ordering.

This combination gives you the benefits of each material where it works best, creating an attractive, practical, and sustainable garden.