What’s the Best Mulch for Native Plants?

Mulch is a great addition to any garden, native or not. It helps to suppress weeds as well as moderate soil moisture and temperature to help your plants thrive throughout the growing season.

You may be picturing something fairly specific when you hear the word “mulch,” likely dependent on the style of gardens you have seen or grown yourself. But as a category, mulch is actually a lot broader than you might have guessed.

There are an extremely diverse group of materials that can be used as mulch. And as with most gardening decisions, some will be better over the long run for your native plants.

Mulch: Proper Use (and Potential Drawbacks) for Native Gardens

Before getting into the nitty gritty of specific types of mulch, it’s necessary to say a few bigger-picture words relating to native plant gardening.

First, for many, the concept of mulching a garden is associated with a particular type of ornamental gardening that is at odds with the philosophy of many who grow natives.

This consists of a formally arranged group of specimen plants a few feet away from each other with wood mulch covering the ground in between to prevent anything from growing there.

This is a largely unnatural way to garden and both requires more maintenance and loses out on a lot of benefits that our native gardens can provide naturally.

In contrast to this is the idea of “living mulch,” where the plants themselves grow to fill in the intermediate spaces. In fact, a large percentage of native gardeners apply no mulch at all once their garden is established.

And this isn’t to say you need to let your garden go completely wild: you can use your design instincts while still benefitting from the concept of “living mulch.” (This is helpful if you desire a more formal looking garden or if you have an HOA with particular requirements.)

Specifically, the way to do this is by using groundcovers, a low-growing plant that will spread to fill in the gaps between the other plants in the space.

That said, however, mulch does a great deal of good for newly planted gardens, for helping to keep invasives at bay, and certain types can improve your soil and help your plants grow better too.

For native gardens that are designed to look more traditional, mulch can be a great way to give them a look of intentionality and formality.

Some potential pitfalls with mulch include laying the mulch too thickly which can prevent oxygen from penetrating into the soil and negatively impact your plants.

The mulch shouldn’t be more than a couple of inches thick and it should not come into contact with the stems; leave a buffer of at least an inch or two.

Other varieties can carry some drawbacks. Some gardeners swear by long-lasting mulch that is dyed a particular color. One critic described it as a desire for “unchanging patterns and hues upon the land” and that obsessing over the mulch color takes away from what should be the focus: “it seems a perfect solution for those who want a garden but don’t want to fuss with plants.”

There are also some larger potential issues with dyed mulches containing recycled wood: “The worry is that there may be preservatives and other contaminants in the mulch that you wouldn’t want in your garden.”

What’s the Best Mulch for Native Plant Gardens?

Aside from the “living mulch” concept previously discussed, there are two broad categories of mulch to be applied to your garden. Mulches can be inorganic (rocks, gravel, landscape fabrics etc.) or organic (leaves, straw, grass clippings, etc.).

Organic mulches are strongly preferred because they release nutrients when they decompose, improving your soil along the way. These nutrients can also help the development of beneficial soil organisms and help your plants grow better.

One particular type of mulch with plenty of adherents is wood chip mulch, which is ideal for weed suppression in newly-established gardens and for disturbed soil.

Long-term, however, thick wood mulches aren’t ideal for wildlife gardens because many invertebrates, such as ground nesting bees, will be unable to burrow through it.

Other gardeners prefer leaf mold, which is made from tree leaves that are in the process of decomposing. It can be bought bagged or made yourself from your own fall leaves.

To make your own leaf mold, gather fall leaves into a pile for them to compost and then be used in the spring.

Alternatively, you can just spread leaves (which can be shredded with a mower to help keep them in place) into your beds in the fall.

According to one expert who swears by it, “everything about this practice seems right. The soil creatures convert the leaves into humus, you’re keeping yard waste on site, and the price is right.”

Deciding to keep your leaves whole also helps insects safely overwinter under their protection.

Other common organic materials that can be used as mulch include pine needles, compost or grass clippings.

In Conclusion: Our Recommendations on Native Plant Mulch

All in all, our verdict is to combine the recommendations given in the previous sections.

First, we recommend using living mulch by planting more densely to let the plants themselves grow, self-seed and suppress weeds and improve soil on their own.

Specifically, you can plant native groundcovers that will fill in over time and thus reduce the need for any applied mulch in those spaces.

And the beauty part is that their short stature will still allow your specimen plants to take center stage.

When you’re just getting your garden started, your plants will be smaller and there will naturally be more space in between them, and keeping weeds at bay is usually a major consideration due to the blank canvas of the newly prepared soil.

So use a mulch, perhaps arborist wood chips which have a variety of benefits and are inexpensive or even free, to get your garden off to a good start.

Then as your garden matures and there is less space left in between your plants, you can switch to leaves, grass clippings or other material you can readily get from your own property for free (if you choose to apply any at all).

Wood chips are also our recommendation for mulching trees and shrubs; just make sure it is not touching the trunk which can stress and kill trees over time.

If you have a favorite mulch you use with your native plants, let us know about it in the comments below.