Last Modified: April 3, 2024

Bark Mulch for Gardens

Unlock the secrets and Dispel the myths

Ornamental garden statue with planter

By Ben Parrot - Landscape Gardener & Amateur Geologist

Overview

Gardening enthusiasts, whether you're just starting out or you're a seasoned green thumb, understanding the role of mulch, particularly bark mulch, is crucial for a thriving garden. Mulch plays a vital role in moisture retention, temperature control, and weed suppression. In addition to its functional benefits, bark mulch also adds a touch of beauty to landscaping, enhancing the overall aesthetic of any garden. Among the various types of mulches available, bark mulch has gained significant popularity for its unique benefits and aesthetic appeal.

Additionally, be sure to check out our 'Pebble Picker' feature, located in the sidebar or menu. This tool facilitates effortless selection and browsing of various decorative aggregates based on colour and type.

Mulched garden bark border next to a path

Key Takeaways

  • Moisture: Bark mulch significantly enhances soil moisture retention, reducing the need for frequent watering.
  • Protection: Offering temperature regulation and weed suppression, bark mulch acts as a protective layer for garden soils.
  • Variety: A wide range of bark mulch types, like pine or shredded bark, cater to different gardening needs and preferences.
  • Myth-BustingWe bust some common myths with the help of Dr Linda Chalker Scott and Dana Richardson. 
Ornamental chippings in a flower bed

Mulch or Bark?

There is some confusion we intend to clear up about the difference between bark vs mulch. Mulch is a broad term that encompasses a variety of materials, including bark, used to cover soil surfaces for protection and improvement of soil health and plant growth. Bark mulch, on the other hand, refers specifically to the protective outer covering of tree trunks and branches, often used as a form of mulch in gardening.

Bark mulch products not only help to conserve moisture in the soil but also suppress weed growth, reducing the need for constant maintenance. Additionally, as the mulch breaks down over time, it enriches the soil with essential nutrients. One cost-effective and sustainable option for gardeners to consider is using bark chippings as a type of mulch for their gardens.

One of the most important aspects of using bark mulch for gardens is understanding the process of mulching, which involves spreading a layer of organic material over the soil surface to improve moisture retention, suppress weeds, and regulate soil temperature. We look at the manifold benefits next.

Landcaping chips close up

Benefits of Using Bark Mulch

One of the key advantages of using bark mulch in your garden is its natural ability to suppress weed growth, allowing your plants to thrive without competing for resources. Another advantage is that it helps maintain moisture levels in your flowerbeds by reducing water evaporation, reducing the need for frequent watering and ensuring your plants stay healthy and hydrated.

Bark mulch, including quality varieties like using pine bark as mulch and chipped bark mulch, offers several other advantages:

  • Aesthetics: Using mulch bark can beautify your garden by providing texture and a uniform look to borders, flower beds and pathways.
  • Temperature Control: Bark mulch acts as an insulator, keeping the soil warm in winter and cool in summer.
  • Weed Control: It forms a barrier to weed seeds and blocks light, limiting the growth of weeds which compete with your flowers.
  • Erosion Control: A natural barrier against erosion, it effectively prevents the loss of valuable topsoil in your garden.
  • Soil Health: As it decomposes, bark mulch adds organic matter to the ground, enhancing its fertility.
  • Disease Resistance: Any mulch can help prevent the spread of diseases by acting as a natural barrier and reducing the splashing of water. This minimises the likelihood of pathogens reaching your plants.
Shrubs growing in pots with wood mulch

Common Applications

Garden bark mulch is not just a staple for aesthetic gardening; it serves a multitude of practical purposes in various settings. Let's explore some applications where bark mulch proves to be an invaluable asset, from children's play areas to the protection of garden slopes.

Children's Play Area

Play bark, which is a type of pine bark mulch, is often used in children's play areas as a soft, cushioning surface. It helps to reduce the impact of falls and provides a safer, more forgiving surface compared to harder alternatives. The depth of the play bark layer is crucial for its effectiveness and is known as critical fall height safety.

Natural wood playground

Pathways and Walkways

In gardens and parks, bark mulch is used to create natural-looking, comfortable paths. It provides a stable yet soft underfoot surface that blends well with the surrounding landscape. It can also be used as a top layer on a wood chip path.

Bark mulch also helps to define and separate different areas in a garden space, acting as a distinct border between flower beds and walkways. Bark mulch can also provide a natural and aesthetically pleasing alternative to lawns, especially where sunlight is scarce on the property or a low-maintenance solution is desirable.

Woodchip path

Around Trees and Shrubs

Applying bark mulch around the base of trees and shrubs helps to protect their roots, conserve soil moisture, and reduce temperature fluctuations, all while keeping the area tidy. In addition, by providing a natural and earthy backdrop, bark complements the surrounding greenery and even the style of the house.

Indoor and Outdoor Potting

One popular method of incorporating bark mulch into your garden is by using it as a potting medium for container plants, providing them with a stable and moisture-retaining environment for optimal growth.

Flower Beds and Borders

Bark mulch is extensively used in flower beds and border areas to suppress weeds, retain moisture, and add a polished look to the garden.

Next, we take a deeper dive into some of the contentious issues surrounding the use of mulch vs bark mulch in garden and landscape design in the hope of serious myth-busting!

Leafy plants growing in bark chippings

Need to work out how many bark chippings your project needs? Try our free bark & wood chip calculator.

Bark Mulch Myth-Busting

In this section, we look at some of the aspects of using bark mulch that aren't covered as widely on the internet. These are often common questions or 'myths' that gardeners of all levels of experience encounter.

Laurel hedge and bark mulch border next to a house

Does Bark Mulch Tie Up Nitrogen?

A common concern is whether using wood-based mulches like bark chips mulch leads to nitrogen depletion in the soil. The nitrogen cycle is a complex process, and while microorganisms do use nitrogen to break down wood chips, this effect is primarily limited to the mulch layer itself. The underlying soil and plant roots are generally not affected. However, it's advisable to use well-composted mulch, like a composted shredded bark mulch, to minimise any potential nitrogen tie-up.

Tilling and Amending Soil with Bark Chips

Gardeners often ponder whether to mix bark chips into the soil. In an excellent YouTube documentary with Dr. Linda Chalker Scott and Dana Richardson, the producer of the Back To Eden film, Linda gives clear advice. Avoid tilling and incorporating bark chips into the soil areas, as this can disrupt soil structure and health. Instead, using wood chips or shredded bark mulch as a top dressing is recommended.

While bark chips can be beneficial as a top layer, incorporating them directly into the soil can temporarily affect nitrogen levels. If you're considering using tree bark as mulch in this way, it's always best to compost it first. This process allows the material to break down, reducing any negative impact on soil nitrogen levels.

Red shrub growing in landscaping chippings

The pH Factor: Does Woody Bark Garden Mulch Acidify Soils?

The belief that woody mulches, such as bark garden mulch, significantly acidify soil is widespread. However, research indicates that the impact on soil pH is minimal. In the same documentary, Dr Linda Chalker Scott said that it could slightly acidify the soil if applied in large amounts directly to the soil (such as in containers) but does not significantly alter the pH of landscape or garden soil when used as a top mulch.

In practice, most plants thrive in slightly acidic to neutral pH levels, and the slight change caused by bark mulches is typically not harmful. In fact, using bark as mulch can even be beneficial for acid-loving plants.

Allelopathic Chemicals in Woody Mulches

There's a myth that certain woody mulches, like those from black walnut trees, release chemicals that harm other plants. However, Dr Linda Chalker Scott suggests this is largely a misconception and that most woody mulches, including those with reputed allelopathic properties, do not negatively impact other plants when used as mulch.

Installing chipped wood mulch in a garden border

Similar Alternatives to Bark Mulch

The following is a list of decorative aggregates which are alternatives to bark mulch. They may offer you a more suitable variation on the primary colour, a more economical option, or a close substitute for cases where the base material may be unsuitable for the project you are creating, e.g. landscaping bark for a play area, where play chips may be safer. The price averages are based on the cost of a standard bulk bag, approximately 1㎥.

Name

Colours

Material

Size

Shape

Availability

Price

brown to red

Bark

10-60mm (0.4-2.4")

irregular

UK, USA, EU

brown to red

Bark

20-60mm (0.8-2.4")

irregular

UK, USA, EU

brown to red

Bark

20-60mm (0.8-2.4")

irregular

UK, USA, EU

brown

Straw

10-60mm (0.4-2.4")

mulched

UK, EU

white or red

5-40mm (0.2-1.6")

chips

UK, USA, EU

white or red

10-40mm (0.4-1.6")

chips

UK, USA, EU

brown

Bark

10-40mm (0.4-1.6")

mulched

UK, USA, EU

brown

Cocoa

5-40mm (0.2-1.6")

shells

UK, USA, EU

Summary

Bark mulch not only helps to enrich and beautify your garden, but it can also insulate and enhance soil moisture retention, prevent weeds, regulate soil temperature, and protect plant roots from extreme weather conditions. Whether you choose one of the many different types of garden mulch, or bark mulch, understanding the properties and effects can help you make informed decisions. Remember, the difference between bark and mulch lies in their composition and specific benefits. By considering these factors, you can effectively use it to enrich and beautify your garden.

1path through a pine forest in morning sun

FAQs

What are the benefits of using bark mulch in gardens?

Bark mulch offers a multitude of benefits for gardens. It aids in retaining soil moisture, reduces weed growth, and contributes to soil health as it decomposes. Additionally, it enhances the visual appeal of garden beds.

How do you apply bark mulch to a garden?

To apply bark mulch, spread a layer approximately 2-3 inches thick around plants and over the soil. Avoid piling it against plant stems or tree trunks to prevent rot and pest issues.

What are the different types of bark mulch available?

Various types of bark mulch include pine and mixed conifer compost mulch. Each type has unique characteristics and benefits, such as cedar's natural insect-repelling properties.

Is garden bark suitable for all types of plants?

While garden bark mulch is versatile, it's important to choose the right type for specific plants. Acid-loving plants, for instance, benefit from pine bark mulch, which slightly acidifies the soil.

Can I use bark mulch for vegetable gardens?

Yes, bark mulch can be beneficial for both vegetable gardens and perennial beds. They help in retaining moisture, suppressing weeds, and gradually improving soil structure and fertility as they decompose. However, the thickness of the mulch and timing of application might vary depending on the specific requirements of the plants and the garden setup. Avoid around very young plants. Strulch may be a better alternative.

How thick should the layer of mulched bark be in a garden?

A layer of 2-3 inches of bark mulch is ideal. This thickness is sufficient to suppress weeds and retain moisture without suffocating plant roots.

Are there any potential drawbacks or considerations when using bark mulch?

Potential drawbacks include the risk of nitrogen depletion as it decomposes, but mainly around seedlings and young plants. It's also important to source bark mulch free from contaminants.

Does mulch help with weed control in gardens?

Yes, bark mulch is effective in suppressing weed growth. It blocks sunlight from reaching weed seeds, thus preventing their germination.

There are many varieties of wood chippings and bark mulch available for your project. Check out them out!

About the author 

Ben Parrot

Ben Parrot, is a landscape gardener and amateur geologist. He is the founder of Outdoor Aggregates, with the mission to create the first encyclopaedia for decorative aggregates. From natural stone through to decorative bark, these aggregates are critical to garden and landscape design, universally.

The problem: There isn't any place where all the different types of decorative landscaping materials and construction aggregates can be found, nor are the specifications of each type readily available. So, enriched by his extensive experience, and inspired by the timeless elegance and raw beauty of stone and rock, etched by nature's artistry over millennia, Outdoor Aggregates was born.