Mulching with Arborist Chips

Reader Contribution by Blythe Pelham

In my recent blog about Garden Thriftiness, I mentioned using free mulch from local tree services in the garden. I decided it was imperative to include a few key facts and pointers about plant and people safety when using said mulch.

You might want to ask the tree service what type of trees are in the mulch mix that they bring you. There are some trees that are not a good mix for certain plants and other trees. For instance, the walnut family (particularly black walnut) is toxic to many annuals, perennials, and trees. If you are able to let bark chips sit for six months, they should be usable without negative consequence because the toxicity diminishes.

Toxicity. Many of us don’t have the luxury of space to let a pile mulch just sit for undetermined amounts of time. For this reason, simply knowing what is in your mulch will be more beneficial. I learned this by a random drop off of mulch that I discovered contained black walnut. I immediately researched and found out about the toxicity. Though my newly planted apple trees were not on the danger list, I wanted to take no chances about their health. While it looked a little strange, I put safer rings of matured mulch around those trees and used the questionable mulch in areas with plants not at risk (see link above for a list of plants).

Disease. Using arborist mulch in this way is not conducive to spreading disease. You should be good to go as long as you are not tilling in fresh mulch as most diseases need easy access to the roots. Topical application is safe in most cases. Remember to leave a small ring of ground around your small plant, shrub, or tree. It is beneficial to most plants to have breathing space around stem or trunk and not to be smothered by the mulch. In fact, it can be very unhealthy for most plants to have mulch piled up around their stem or trunk.

Composition. Tree service mulch would drive anyone with OCD bonkers. The composition of the pile is quite diverse (see photo above). Most piles include long sticks (that can poke and puncture) and parts of branches, shredded leaves or needles, composted matter from dead wood, and pockets of mold. This latter could be a problem for people with certain allergies or pose a health risk if moved without a breathing barrier mask.

The arborist-mulched bed looks far more natural, in my opinion, than those covered with purchased piles or bags of uniform mulch. I have both types of bed in my own garden. Some people prefer the neat look of the bagged mulch as it helps frame the plants that they are highlighting. I have to say that even though I like the convenience of toting bags around, I prefer knowing that I am living more sustainably with my tree service arborist chips and I like the diverse nature. It also allows us to more easily clean up around our river birch because we can simply toss the smaller litter onto our beds and it blends right in.

Depending on the availability, you can vary the depth as needed. While the most beneficial depth of mulching with chips is four to six inches, I find that my beds end up with an average of three to four inches. The result is a few more weeds to pull but I use what I can get for low or no cost and that’s important to me.

If you don’t have easy access to a tree service willing or able to leave the gifts of their labor in your driveway like I do, you can watch for end-of-season sales. Last fall I had no way of knowing that my early spring deliveries of mulch would be so abundant so I took advantage of a sale at Lowe’s and stocked up on bags of mulch (see photo above).

Benefits of Mulching

Why mulch at all? I practice this way of gardening to keep down weeds, help maintain an even moisture for my trees and plants, and to provide a slow, steady addition of organic material to my soil. Ideally, I add more mulch every two to three years. Moving mulch is a large job but it cuts down on maintenance time throughout my garden between overhauls and I think that is worth the effort.

Above is a photo of a recently covered bed of tree mulch (the green bits are pine needles that came in the mix) surrounding one of my vegetable beds that has been covered with visqueen cloth and straw and is ready for planting. This particular bed (now under the arborist chips) was covered in straw. I simply added another layer of cardboard and topped it with the newly delivered tree mix. I’ll be able to leave it barren or add new plants in the fall or coming seasons.

Blythe Pelham is an artist that aims to enable others to find their grounding through energy work. She is in the midst of writing a cookbook and will occasionally share bits in her blogging here. She writes, gardens and cooks in Ohio. Find her online atHumings and Being Blythe, and read all of her MOTHER EARTH NEWS postshere.

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