March 26, 2009

Arboricide Exposed! My Dirty Little Tree-Planting Secrets

What horrors lurk beneath that mulch?

I used to work at a nursery that specialized in selling trees. People came from all over the state for the large selection - nine acres with thousands upon thousands of trees of all types and sizes.
How to properly plant all those trees was a common customer question. I'd tell them it was a bit of a balancing act. If they didn't remove the burlap and wire, the tree's roots would strangle it in a few years. If they removed the coverings but let the rootball fall apart, the tree would die right away. The key was to remove as much covering as possible while keeping the rootball intact. Containerized trees, on the other hand, needed their roots loosened up a bit after the pot came off.
So when hubby and I purchased and planted fourteen trees in our yard last fall, I figured that I knew what I was doing. I often buy plants from big box stores, but I ordered my trees from the local nursery so I could get the best quality. It was a big investment, though the nursery gave me a volume discount and free delivery. Six 'Spring Snow' crabapples, five 'Shademaster' honey locusts and three 'Kwanzan' (or Kanzan, as you prefer) flowering cherries were ordered and delivered to our driveway in late September. They were all growing in 15-gallon-sized pots, as that was what the nursery had been able to find for me from their wholesalers.

Is this honey locust tree doomed?

Dear hubby - dear, dear, hubby - cheerfully set about digging the holes for the large rootballs. We discovered that a pick axe was the tool of choice for digging in our incredibly rocky soil, once we got beneath the thin layer of 'sandy loam' that the builder spread before seeding the grass. After hubby finished digging the first hole - the same depth as the rootball and 3 times as wide - he used a hammer to loosen the pot from one of the cherries and pull it off the rootball. He pulled the rootball out and exposed not soil, but ROOTS! Circling roots! A few inches of potting medium showed at the top, but the rest of the rootball looked like a thickly woven wooden basket.
Oh, dear, I thought. That's not a good sight. When I went to the nursery to inspect the trees before delivery, the nursery guy told me not to disturb the roots very much when planting. But I knew that circling roots have a hard time changing direction to grow out into the soil, and they can eventually strangle the tree as both roots and trunk increase in girth and crush each other. So I used my Felcos to cut the roots - from top to bottom - at three places around edge of the rootball. Then I used the tip of the clippers to loosen the roots all the way around and on the bottom.
The three cherries and the five honey locusts had extremely pot-bound roots, so they all got the same treatment. The crabapples were a bit smaller and the roots weren't as bad, but they were still cut and loosened before planting.

Will this crabapple survive despite flawed roots?

After all of this root-cutting, I felt somewhat unsettled. Had I done too much damage? Would the trees survive next summer or shrivel in the heat? This worry has been lurking in the back of my mind for months.
And then, during my gardening-book-reading-bonanza this month, I read a book called The Informed Gardener, by Linda Chalker-Scott. The author is a professor at the University of Washington who writes occasional myth-busting articles for master gardeners, some of which are gathered into this book. The section on tree planting nearly gave me an ulcer. Professor Chalker-Scott writes, "Containerized plants are notorious for concealing fatal root flaws." That statement exactly described my poor trees! She recommends removing ALL of the potting soil at planting time to fully expose the roots, which can then be correctively pruned and planted properly (I'm assuming this method works best when the tree is dormant). In a moment, the pendulum swung wide and my worries about disturbing the roots too much changed to worries about all the fatal root flaws I had surely missed!

What kind of lifespan can this cherry tree expect?

I get enormous satisfaction from taming tangled branches into an orderly composition with my pruners. The idea of neatly trimmed roots, growing outward in a perfect starburst, is very appealing to me. I have this urge to dig my trees up, some of them at least, and check to see just how misshapen the roots are. In a few decades, will my trees swoon and die from hidden defects? Hubby raised an eyebrow at the redigging idea, though, and I'm not that good with a pick axe. And needless to say, digging up plants to inspect their roots is generally detrimental to their health.
So now I'm living with fourteen dirty secrets buried beneath several inches of mulch. I'm supposed to know how to plant trees, but might have botched the job in my own backyard. I actually feel unsure about the best way to plant. Would barerooting a tree work in harsher climates than Chalker-Scott's Seattle area? At what point is a tree too rootbound to ever recover? As for my trees, I'll just keep watching, hoping for the best, and reporting about their success or failure on this blog.
You can read Professor Chalker-Scott's myth-busting articles at her website. Here's the link to one tree planting article. You might be surprised at her findings on such topics as soil amendments, bonemeal, compost tea and drought-tolerant plants. Let me know if you learn something new - I certainly updated many of my ideas after reading her articles.

6 comments:

  1. VW, last week in our Learning Garden the Tree Steward class had an arborist out and they used an air spade to check the roots on a few of our trees. It was amazing to see the results. Like yours we had some that had some girdling roots. One recommendation was to prune the large encircling root (it was about the size of my wrist). We were about three weeks from last average killing frost, so while the trees are just emerging from dormancy, they won't be too stressed with the root pruning. Apparently the circling of roots in the container happens more often than we think. As the trees get moved to larger containers their roots need to be opened so as not to continue to circle the pot. If you think your trees are really circled root-wise, perhaps now, before they are established, you can check the roots.
    I will read through the articles. If you are intersted in seeing the photos I took on the root cutting on a Linden, give me your email via blotanical.com it is a pretty amazing lesson.

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  2. I hope they do well for you VW. I think that knowing you took you the felcos and spread the roots out would help make me sleep better at night. The trees will work it out. Only time will tell and I'm hoping for the best!

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  3. Hi VW

    I'm no tree expert, however my two penny worth is this.

    I planted a young umbrella pine (pinus pinea) two years ago last Autumn in a spot where a large walnut tree had been growing previously. The walnut had blown over in a storm and after 4 days of cutting with a chainsaw together with burning the stump out, the tree was removed.

    Within a few days of the tree being gone I then planted the young pine in the same spot. I really didn't improve the soil much and man handled the tree out of its pot. The young tree was completely pot bound so I tore at the roots and then duly planted it.

    This pine is a picture of health at the moment. It has grown ahead of expectation (it's a slow grower) and in an area previously occupied by a tree which in a funny way is territorial. That is, the jury is out, but it seems that walnut along with a number of other trees emit a kind of natural herbicide which makes it difficult for other things to grow in their immediate vicinity. It's the order of things.

    Now it's obvious to me that you would and have given your trees far more professional TLC. I'd be loathe to dig them up again. It seems you've dug a sensibly large hole for the root ball. Surely those feeder roots will find their way into the friable soil that you backfilled.

    I wouldn't be forthcoming in terms of irrigation either, unless you are in a real drought. Let them find their own way.

    Finally, I've planted plum, cherry and peach trees in a little garden which is attached to a place I rent out near here. All were suitably vandalised by me at planting time and all are doing fine some two years on.

    I might just be lucky or not in a few years, but I have a sneaky feeling yours will be OK. Please feel free to disregard, as I said (and have now proved) I'm no expert but...

    Rob

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  4. You chose such pretty trees! I bet you did just fine with what you did. I worry about some of those same things. I know some of the trees we planted when I was still new at gardening were not planted correctly, but all of them, some 10 years old are still doing fine. I look forward to seeing those blooms, some will be blooming fairly soon I bet.

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  5. Oh my, I am glad to not be planting trees these days. It's like raising kids; we worry that we will mess them up!..I do
    understand the concern...the investment is big, even if we get a good discount. gail btw...thanks for the planting lesson.

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  6. VeeDubya: Great post. I started my horticulture career with the hobby of bonsai and find pruning to be a most satisfying and constructive past time. It's like having a time machine that allows you to imagine what the plant will look like five or ten years hence.

    Hey, I posted a response to you comment at my blog about house plants. check back...bg (alias GWG)

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