Wonderful wood chips

I’m in love…with arborist wood chips.  These are not your beauty barks or other packaged mulches, but the chipped branches and leaves fresh from the tree crews. It’s a great way to keep this resource out of the landfill – and don’t even get me started about using this great mulch material for a “biofuel!”

I’ve written about wood chip mulches a lot, but thought today I would post some photos to show you how well they work in suppressing weeds and promoting growth in restoration sites.  We published a paper on this in 2005, though we’ve been using them in ornamental and restoration landscapes for about 10 years.

Here’s a recent project: a wetland buffer enhancement was being installed in an area that was covered in Scot’s broom (Cytisus scoparius) and blackberry (Rubus discolor):

Heron's Glen-6

We had a brush cutter mow it to the ground, then put a foot of wood chips down.  Later, we planted poplar, ash, willow and alder on the site:

We had to keep records, both written and photographic, for the county who monitors wetland projects.  So we took photos every year at the same points for comparative purposes.  Here’s what part of the site looked like immediately after planting and then after 5 years:

That’s not to say that we haven’t had to battle resurgent blackberries.  They migrate over from the wetland itself (which we can’t touch) and tip root.  But the increasing shade and competition from the trees has weakened their ability to take over, and the Scot’s broom has been gone for years.

So that’s one reason I love wood chips.  I’ll do a follow up some week showing how they can be used in the home landscape.

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Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

22 thoughts on “Wonderful wood chips”

  1. Nope! You can, of course, but you don't need to. Plus, it smells great when it's fresh. No issues about either disease or nitrogen deficiencies (I can send links to those materials if you want them).

  2. I've used fresh wood chips for my ornamental garden in the past because I was too cheap to buy mulch. The only issue I had is that it breaks down more quickly than bark mulches, so it must be replenished more often.

  3. Cheap is good! And you're right, Dave, they do break down faster. At home, I generally put down about 6 inches in the spring. It settles pretty quickly to about 4 inches. In general, that lasts until the following spring.

  4. i remember clearing glossy buckthorn patches back when i worked for a park district in the midwest. we would then use these chips in our parks. quite a few weed seeds in that stuff! i guess its a trade-off for the cheapness.

  5. You're right, JD, the quality of the chips can be variable depending on the source. I try to avoid loads that have English ivy, poplar and willow in them as younger stems can easily reroot. Cheap is good as long as it doesn't add to your labor costs with increased weeding!

  6. Nothing makes me happier than a load of woodchips gently steaming in the driveway. I view arborists chips as instant duff. What could be better for woodland plants like rhodies?

    Breaking down is not a bad thing. It enriches the soil. Bark, being suberized, never really breaks down to enrich the soil. My soil is sandy. It needs all the organic matter it can get.

    I guess the fact that it takes me a few days to spread the chips is a good thing. The pile heats up to 130 degrees, and kills seeds and twigs.

  7. Wow, Deirdre, you sound like my clone! I too have a steaming pile of chips in the driveway every spring. Since I prefer conifer chips, it smells like Christmas. And it keeps your hands warm on cold spring days!

  8. I recently removed 50 year old junipers from a steep hillside. Want to mulch before planting. Will arborist chips work or will they slide down the hill? As an alternative I can get "compost" from the landfill. It has a high content of shredded brush, leaves, and grass, but hasn't really been composted yet. The particles would be finer in the "compost". Suggestions? Thank you!

  9. Phyllis, you can use them on slopes. What we've done is a couple of things: 1) lay down coir cloth (like burlap, kind of) over the top to keep them in place or 2) create deadfall terraces along the slope to keep the chips back. You can do this easily with large branches/small tree trunks, held on the slope by two wooden stakes on either end on the downhill side of the timber. <br><br>
    You can also use the other compost-type material, but you can't lay it on thickly. It tends to reduce water and air movement, given its finer texture.

    1. Hi—we recently moved to a house in northern NJ, and our backyard is a steep slope down to a small river. We love the view but along the switchback path to the river are wedges of completely overgrown, tangled and prickly brush, which we’d love to make a bit more attractive and safer for our 2 kids. We’re wondering about covering it now (before it grows up again in the spring) with a thick layer of wood chips which is infinitely less expensive and more environmentally sound seeming than most of the options landscapers have presented us with. Our worries are that we have read that it can harbor bugs and termites and lead to significant problems, and that it will all just slip right down the slope. Do you have any insights on this? Thanks so much for your help!!!!

  10. I have enjoyed reading the information about wood chipping. Really, entire discussion is more helpful and all the tips are more effective too. I am very glad to go through this kind of helpful article. Thanks for sharing a nice article.

  11. My husband and I learned about the value of wood chip through your Great Courses lectures. We live in north Florida. Is pine mulch a suitable option please? Many thanks!

  12. I am a hobby wood worker and have raised bed vegetable garden. Today Dec 31, I planed some alder and now have a large bag of wood chips. Rather than add these to my garbage, I have several alternative uses possible. Which if any would you recommend? 1. Add as a ground cover around various pants around the house (rhododendron, barberry, small evergreens; 2. Mix these chips in with my raised bed soil? Is yes, should I do it now or when I add a processed manure in the spring with mushroom mulch? 3. We have recently added fresh topsoil ( acidic) behind a new concrete terrace wall. The plan is to plant some arborvitae in the spring. Is there any benefit to mixing some of the alder chips be in with that soil?
    Thanks in advance.

    ORGramps (Rex)

    1. Hi Rex –

      Sorry for my late reply – COVID19 has just escalated my email and online work load! Anyway, do NOT mix your chips into the soil, but yes, do use it as part of a mulch layer. It will be rather inert, since this is processed lumber, but may adding some shredded leaves or even a little manure that will improve its functionality.

  13. Since I became aware of your advice on using arborist chip mulch a few years ago, I was thrilled to get some from a friend who had a couple of trees taken down. Since there were also a lot of large-ish bark pieces lying about, I brought them as well, and covered my garden path. The wood chip mulch has been a total success (thanks!) but I wonder if you would not have approved of using the bark in the path? btw, I am committed to doing the right thing, and am grateful to you and your fellow professor-experts to steer me in the right direction.

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