Repotting Tip ‘O the Month-

Many trees like their roots far away from anything saturated, which is the bottom of the pot. Two in particular, pines and azaleas. And in muddling about the Western bonsai world I’ve been haunted by the number of pines planted in very shallow containers.


The pine that Matt Reel is working on is in a deep pot, and this is typical for pines. This has as much to do with horticulture as aesthetics.

‘Rules’ are slippery things, as anything in bonsai has exceptions. So consider this a ‘slippery-rule’, a ‘you might want to consider’, and not necessarily a ‘darn it you’d better do it or get swatted with a bamboo chopstick’ sort of offering—-but please, in general, get your conifers, particularly pines, in deeper pots, and your deciduous might go in shallower ones because you can get away with it horticulturally.


This maple in Shinji Suzuki’s tokonoma is in a pot typical of this kind of tree. It works better aesthetically, in two ways. A shallow pot will make the nebari continue spreading, and the delicacy of the trunks is enhanced by a shallower pot. But a maple is also a tree that appreciates water. And a shallow pot will retain more moisture than a deeper one, in a soil-to-soil relative way. It’s a wetter pot.

Now the disclaimers. Breathe in. (That’s for me).

You can certainly plant your pine in a shallow pot (loud thwack of a chopstick on my fingers), but consider mounding it. Mounding and getting live moss established will help greatly in drying out the root ball the way a pine wants it. Mounding helps drain excess water, and moss prevents excessive drying of the surface, which might sound like an oxymoron but it works.

The happy zone of any tree is fairly specific. The top often dries out a lot. The bottom might stay too wet. And the pine likes the middle zone. So most pots for pines should be deeper to broaden that happy zone. Or, if you mound a tree by 3″ above the lip in a 3″ pot, then you’ve essentially given the tree 6″ of growing space and a fairly broad happy zone. Shallow pots for conifer bunjin, clumps, and forests are good examples where mounding is appropriate and often used.


Pine in a shallow pot, mounded.

Without an erosion free and water retentive surface, however, like live moss, mounding is unlikely to be a happy equation. Search for ‘moss’ on the search field in the upper right of my blog, and you should find some moss articles there and how to establish it. I think I wrote a few.

Happy potting! Or resting, if you’re in the Southern Hemisphere.

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  1. Hi Michael,
    I could not find the way to the moss info on this blog.


  2. Tim Weckman says:

    Nicely done Michael. You have given the principle and the reasoning behind the principle. Much needed in helping to deepen understanding of our bonsai practice

  3. Ray says:

    Great tips Michael, in BC we havea lot of rain and root rot has been a problem for black pine. I keep them dry under the eves and have a free draining mix.

  4. Michael M says:

    Thanks Michael, This brings up another observation. While repotting several black pines this year I saw several that had a mass of roots around the bottom of the pot, pushing the root ball up an inch or two. Why would these healthy roots be in the bottom? Am I not watering enough? I am in Northern California.

    • crataegus says:

      It could be that your watering interval is too long. Curiously, if your soil is either too fine or too coarse the happiest roots end up on the bottom. But if the top is drying out too fast that might be your problem.

  5. bonsai eejit says:

    Reblogged this on Bonsai Eejit.

  6. paulkenni says:

    Great article, thanks. It’s less resting and more waiting eagerly down here in Cape Town =D

  7. Hi micheal
    Just returned from a little hike and found an area full of small contorted
    Arbutus . Pulled gently on one and it just fell out of the gravel. Potted up in sand and 1/4 inch driveway gravel. I know they are difficult but taking a chance. Do you have any experience with the tree.
    Qualicum Brian

  8. Steve Moore says:

    Thanks for the “happy zone” term; makes the concept easier to remember. 🙂

  9. Ric says:

    How I wish I could find deeper pots than 2 1/2 inches!

  1. […] good place to start is with an article by Michael Hagedorn (Crataegus Bonsai) about pot depth for various type trees. You don’t see much on this topic, […]

  2. […] good place to start is with an article by Michael Hagedorn (Crataegus Bonsai) about pot depth for various type trees. You don’t see much on this topic, […]

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