“Save the planet, (learn how to) plant a tree”

I like catchy memes as much as the next person. They’re easily memorized and passed on. But “Save the planet, plant a tree” has always bugged me for two reasons. First, and probably most importantly, this simplistic mantra absolves people of doing MORE to improve our environment. It’s a “one and done” approach:  “Hey, I planted a tree today, so I’ve done my part.” That’s hardly a responsible way to live in a world where climate change is a reality, not a theory. Planting trees (and other woody plants) needs to become part of a personal ethic dedicated to improving our shared environment, and that includes reducing our carbon footprint in MANY ways.

Second, and more germane to this blog, is that most people don’t know how to plant trees (and that includes an awful lot of professionals who should know better). Planting trees properly requires an understanding of woody plant physiology and applied soil sciences. Otherwise, newly planted trees are likely to die due to one or more problems:

  • Poor plant species selection
    • Mature size too large for site.
    • Species not adapted to urbanized conditions. This includes insistence on using native species whether or not they tolerate environmental conditions far different from their natural habitat.

  • Poor/improper soil preparation
    • Working amendments into the soil before, during, or after planting. Your goal is to keep a texturally uniform soil environment.
    • Digging a hole before seeing what the roots look like. It’s like buying a pair of shoes without regard to their size.

  • Poor quality roots
    • Most roots found in containerized or B&B trees are flawed through poor production practices. If you are using bare root stock, you don’t have to worry about this problem.
    • Can’t see the roots? Well, that leads to the next problem.

  • Improper root preparation
    • No removal of burlap, clay, soilless media, or whatever else will isolate the roots from its future soil environment. Take it all off.
    • No correction of root flaws. Woody roots don’t miraculously grow the right direction when they are circling inward. They are woody; it’s like trying to straighten a bentwood chair.
Just try to straighten those circling, woody roots.

  • Improper planting
    • Planting at the wrong time of year. It’s best to plant trees in the fall, when mild temperatures and adequate rainfall will support root establishment and not stress the crown.
    • Not digging the hole to mirror the root system, especially digging too deep.
    • Failing to place the root crown at grade (which means the top of the root crown should be visible at soil level). Look at forest trees if you are not familiar with what a root crown looks like.
    • Stomping or pressing the soil around the roots. That just eliminates the air space in soil pores.
    • Adding “stuff” like transplant fertilizers, biostimulants, etc. They are not needed and you risk creating nutrient imbalances when you add “stuff.”
The tape marks where the burlap ended – a good 10″ above the root crown.

  • Poor aftercare and long-term management
    • Failing to add arborist wood chips as a mulch on top of the planting area. Regardless of where you live, natural woody material as a mulch is critical for root, soil, and mycorrhizal health.
    • Failing to irrigate throughout the establishment period and seasonally as needed. Trees will continue to grow above and below ground, and without a similar increase in irrigation the trees will suffer chronic drought stress during hot and dry summers.
    • Adding fertilizers of any sort without a soil test to guide additions. Trees recycle most of their nutrients; don’t add anything unless you have a documented reason for doing so.
There is nothing better for roots, soil, and beneficial microbes than fresh arborist chips.

That’s a lot to think about when you are planting a tree – but when you understand the science behind WHY these actions should be avoided, then you can devise a better plan for planting. And if it all seems to be too much, I have created a twelve-step planting plan that might be useful. Please feel free to share it widely!

Published by

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

13 thoughts on ““Save the planet, (learn how to) plant a tree””

  1. Sorry for the second entry. I couldn’t edit the other comment. Regarding right tree in the right place, would you say it is a benefit to the environment to plant 20 Princeton elms? How about if I told you they were planted in 4 foot by 4 foot by 4 foot planter boxes in a rooftop garden? Yeah, I didn’t think so! Yes, true story!

    1. I guess you would have to weigh the use of resources (water, etc.) to keep them alive with the benefit – but if it were me, I’d probably have done the same sort of thing if I lived somewhere where typical tree planting wouldn’t work.

  2. Under “Poor improper soil preparation”, you wrote “Working amendments into the soil before, during, or after planting. Your goal is to keep a texturally uniform soil environment.” I cannot imagine how one can add amendments without changing the texture of the soil in the planting hole, making it different from the surrounding soil. Would you help me understand how one can amend the soil without changing the texture? Or do you mean that by adding amendments into the soil will alter the texture to the detriment of the tree? I am confused.

  3. Thank you for your great advice. I have a question: I just this week purchased some 1 and 2 gallon containerized shrubs–they are still mostly dormant. (the Flowering Almond has small flower buds.)

    Should I plant them now before they leaf out — washing/pruning the roots and treating them as bare-root, or should I wait and keep them in the containers until fall? It would seem that as far as the plant is concerned, “exchanging” the pot for a hole in the control would be easier now before the roots really get growing.

    I’m in Vermont. Soil is unfrozen but still chilly. (The plants are elderberry, rose of sharon, flowering almond, raspberry.)

    1. It’s better to wait until fall. The plants will be putting their stored resources into crown growth as they are breaking dormancy. Roots won’t establish well. It’s best to wait until fall, when they’ve gone dormant again. Roots don’t go dormant and as long as they are in a moist, mulched soil environment they will establish over the next several months.

      1. Oh, thank you so much for your reply. You should write a book! Now I know what happened to that one forsythia and the blueberries–(sad laugh.) Do you mean that I should give them the “bare root” treatment in the fall?

        1. Actually I’ve written several 🙂

          Yes, do bare-root them in the fall. You can actually place them out in your landscape in their containers this year so they become adapted the light regime. I do this every year – I scalp the lawn to the ground, mulch deeply with arborist wood chips, then sink the container in the wood chips. In the fall, I move the container and the chips underneath, then bare-root and plant.

          1. Oh, such a good idea! And I will get your books straight away. Is Amazon the best place?

            Your advice encouraged me to mostly purchase bare root plants and so far zero of the bare roots have died (and they grow great) and the container plants…well…50% I’d say? My favorite trick the sellers do is sell you a “one-gallon” plant that is just a 3″ plant in huge pot of bark. Now I have to nurse them along for two years…

            Funny thing is that I actually have a degree in Horticulture but they never discussed any of this stuff. (Unless I really wasn’t listening? lol) They taught all this stuff about viruses and soil chemistry and insects and fertilizer rates and post-harvest physiology and in the end I could barely plant a tree! Ha! (In all fairness to the college, it was mostly focused on large scale agriculture.) Anyway, thanks again!

            1. You are right – they don’t teach most of this stuff in horticulture. It’s the applied outcome of our theoretical education. And sometimes the two don’t mesh very well! It took me many years to drill down through many of these “accepted” practices to discover that many aren’t grounded in science but rather just word of mouth.

  4. Hi Linda, can you please comment on tree spacings? Gardeners in my city seem to space every tree about 1-3mts apart. I don’t know which species the trees are that I transplant, but I don’t mind if their growth is a bit stunted, or enhanced by a very close neighbouring tree. But I do hate the thought that I’m going to kill them by overcrowding. Perhaps I’m just recklessly playing russian roulette and I should stick to the spacing status quo in my area. I’m certain it’s a broad topic but I would really appreciate any direction that you could provide to me. It is quite a contentious topic within my family. Thank you kindly.

    1. Tree spacing is determined by mature species size, both the canopy and height. Tree roots can spread out 2-3 times the height of a tree, e.g.if a mature tree is ~20′ feet tall, the roots can spread 40′-60′ away from the trunk. Canopy spread also help determine spacing, the wider the canopy, the more room it needs.
      Think of it as living in a small apartment and you bring the cute little puppy home only to find out it’s a St. Bernard. Crowded much?
      Not planting trees or shrubs in a straight line can allow for a little closer planting. Plant them offset from each other, in a zig-zag. This also makes for a better windbreak and gives more privacy as the trees grow and fill in.

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