Types of Wood Chip To Avoid in Gardens

  • By: TheWalledNursery
  • Time to read: 5 min.
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If you have a garden, there are some types of wood chips you’ll want to avoid using. These include eucalyptus, black walnut, and the tree of heaven mulches. These wood chips can leach chemicals into the soil that are toxic to your plants!  

The best wood chips to use are the ones you can find locally.

Types of wood chip to avoid in gardens explained
Types of wood chips to avoid in gardens

They’re much more sustainable and help keep the chips out of landfills.

Overall, you’ll want to carefully consider the types of wood chips that you include in your garden. 

What Wood Chips Should I Avoid? 

When choosing wood chips for your garden, you’ll want to consider what you use carefully.

The wood chips break down, creating a mulch for your plants. However, not all plants will love every type of wood chip. 

Some types of wood chips release chemicals into the soil that are toxic to some plants.

Wood chips to avoid
What Wood Chips Should I Avoid? 

For example, eucalyptus, black walnut, and the tree of heaven bark can kill young plants or even prevent them from sprouting in the first place!  

If you want your garden to thrive, you need to ensure that your wood chips don’t leach allelochemicals into the ground.

These chemicals are what become the toxins that can harm young plants. 

Allelochemicals include any chemical made by a living creature, but they have adverse effects when interacting with other organisms.

Because of this, you must avoid wood chips that contain these harmful components to keep your garden thriving. 

Why Shouldn’t I Use Eucalyptus Chips? 

Eucalyptus releases allelochemicals into the soil as it breaks down, causing significant damage to plants!

The chemicals can cause plants to turn yellow or even die.  

Don't use Eucalyptus chips garden
Don’t use Eucalyptus chips

These chips also have a unique effect on soil- they remove nitrogen from the ground!

As a Gardener – You may already know that nitrogen is an essential part of your soil for growing a healthy and abundant garden. 

Eucalyptus is also toxic to many plants and creatures living in the soil. Overall, you shouldn’t include it in your garden! 

Why Shouldn’t I Use Black Walnut Chips? 

Black walnut chips are very bad for crops!

The bark contains juglone, which is toxic to a variety of plants, including: 

  • eggplants 
  • asparagus 
  • tomatoes 
  • peppers 
  • potatoes 

If you’re growing any of those crops at home, you’ll want to make sure that you avoid using juglone.

Black Walnut tree mulch bad for plants
Black Walnut tree

Black walnut wood can easily harm these plants, stop their growth, or cause them to wilt!

You’ll need to choose other types of wood chips instead. 

Why Shouldn’t I Use Tree of Heaven Chips? 

Tree of heaven wood chips also emit high amounts of allelochemicals into the ground.

Ailanthus altissima tree
Tree of heaven

These chemicals can kill plants or prevent young seedlings from sprouting fully.

Even when the tree of heaven is alive, its roots can kill nearby vegetation. 

What Wood Chips Can I Use Instead? 

Luckily, there are plenty of other wood chips that you can use instead of these!

You’ll want to consider your location and choose a local option.

That way, you can receive more benefits and have a sustainable source of wood chips. 

Here are some alternatives that will benefit your garden greatly: 

  • Pine bark mulch 
  • Arborist wood chip mulch 

Pine bark mulch that’s finely ground is best.

Pine bark mulch gardening
Using Pine bark mulch

It’s very light and airy, allowing young plants to emerge from the ground easily. It also conditions the soil and adds more nutrients to it as it breaks down.

However, you’ll need to keep the chips on top of the soil. That way, they don’t absorb the nitrogen there. 

For Arborist Mulch – They are natural and don’t contain any dyes. These mulches are great for gardens, and you can usually find them locally.

Some tree removal services will even offer to bring them for free! 

In short, you do have plenty of options for wood chips!

Make sure you research anything that you want to use first. That way, you won’t accidentally add something harmful to your garden. 

Why Should I Use Wood Chips in a Garden? 

Wood chips, or mulch, have a variety of uses in a garden- especially if you’re growing your own vegetables!

Veggie plants love many nutrients that wood chips add to the soil, helping them grow. Plus, there are more benefits to consider. 

Mulch Holds in Water 

Seeds and young plants require a lot of water!

Adding mulch provides a top layer to your soil, holding in more water for longer periods.

Using wood chips guidelines
Using wood chips

Since the water won’t evaporate into the air as easily, your plants have more time to drink it.

You also won’t water your garden as frequently because of this. 

Mulch Enriches Soil 

Organic mulch also enriches your soil in a variety of ways.

It supplies the soil with more nutrients as it breaks down.

Your plants take in the nutrients, allowing for fuller, healthier plants that produce more vegetables. 

Much Stops Weeds 

If you feel like you’re constantly pulling weeds out of your garden, adding mulch can help!

Wood chips can block weeds before they sprout, so you won’t have to deal with them.

You’ll find that you spend less of your gardening time weeding after adding a good amount of chips to the top of your soil. 

Overall – Many benefits come with adding wood chips to your garden. Although, it’s good that you choose the correct types of wood chips. 

Can I Use Conifer Wood Chips? 

Many gardeners have concerns about using confider wood chips in their garden.

Pine, fir, spruce, and hemlock trees create wood chips that are highly acidic.

Using conifer wood chips garden
Using conifer wood chips

However, as the wood breaks down, the chips don’t change the soil much, making it safe to use in a garden! 

You should use conifer wood chips with mulch from other types of trees. That way, the chips don’t impact the pH level of your garden soil too much. 

Although, you can use conifers for acid-loving plants without worry!

Some plants that would love conifer wood chips include:

  • blueberries
  • cucumbers
  • garlic
  • squash
  • tomatoes
  • celery
  • cauliflower
  • and carrots

You can always test soil pH levels at home if you have any concerns. 


We recommend staying away from eucalyptus, black walnut, and the tree of heaven mulches as these wood chipping can kill young plants and prevent them from sprouting.

The best Wood chipping to use, Pine bark mulch, and Arborist wood chip mulch. These can be beneficial to your garden. See benefits above.

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