Best Bonsai Trees for Beginners – American Hornbeam


My monster American hornbeam. The trunk base is 6″ in diameter.

One of my favorite and best bonsai trees for beginners is the American hornbeam, or Carpinus Caroliniana. It is a member of the birch family, Betulaceae and is an understory tree, growing to only about 30’ in height.

The bark is gray and smooth, the leaves a dark blue-green and shiny, elliptical, long-pointed at the tip, and sharply doubly saw-toothed.

Best Features

Growth habit: American hornbeam grows continuously from spring through the end of the growing season. This hastens training, as it can be wired and shaped as many as three times during each season.

Leaf size reduction: hornbeam leaves reduce well, from 4-1/2” in length to less than 1”.

Ramification: facilitated by the continuous growth habit. For larger collected specimens with no branches at all, it’s common to see the tree bud and produce shoots that in turn produce secondary shoots in the first year.

This is evident on the specimen pictured here, which was collected in 2010 and photographed a year later.

Root growth: very vigorous. Be sure not to disturb the root zone for newly collected specimens during the first year, to allow the tender new roots time to harden off.

By year two, your hornbeam can be potted into a bonsai container provided you’re satisfied with the development of the branching and no longer need vigorous recovery growth. Once your bonsai is potted, plan on root-pruning and repotting every second year.

Worst Feature

Hornbeams are susceptible to borers. When they emerge as adults from the tree, you get a round hole in the trunk that won’t ever heal, but worse than that you can expect the tree has been weakened and will either succumb fairly quickly or, if it survives, will grow poorly for some years afterward.

There’s no good way to tell in the wild which specimens have been stressed enough to make them susceptible to borer attack, so when you collect hornbeams there’s always a chance you’ll bring home a tree that’s overly stressed.

The good news is, once a tree has recovered from collection and is healthily on its way to becoming a bonsai, I’ve never seen a borer attack. There’s never any guarantee, of course, but it’s nice to have some assurance.

Sources of Hornbeam

American hornbeam is very widespread in Eastern North America, ranging from the Deep South all the way to Canada. It’s found mainly in moist, rich soils near or along streams. Specialty bonsai nurseries also offer hornbeam specimens.

If you collect your own: hornbeam has a stout wood, so I always recommend use of a cordless reciprocating saw to make the work easier.

Cut the trunk to roughly 12-24”, then sever the lateral roots to within 4-6” of the trunk. Next thrust the blade up under the tree and sever the taproot.

Most trees should be out of the ground in under five minutes using this tool.

Once it’s time to pot the tree initially, first wash off all the native soil. Then re-cut the roots closer to the trunk in anticipation of the eventual bonsai container.

New roots will sprout mostly from the cut ends of the larger roots, so dust near the ends with rooting powder. Pot in prepared soil. Be sure to bury the surface roots to ensure they don’t dry out as the tree recovers.

As a final step, seal every cut on the trunk that’s ¼” or greater in diameter with cut paste.

Other Information

Watering: with the proper well-draining soil mix, you can water as often as needed without fear of root rot. Roots tend to grow to the edge of the pot as they extend, making them prone to scorching in the summer. This is reflected in browning leaf edges. Provide shade during the high heat of summer to minimize this problem.

Feeding: either organic or inorganic at full strength during the growing season. No special requirements.

So What Do You Think?

This is a great tree for beginners or even seasoned bonsai artists. But I would really enjoy hearing your thoughts and your suggestions! I’m always happy to answer any questions you have. Just leave your comment(s) below and I’ll get back to you right away.



12 Replies to “Best Bonsai Trees for Beginners – American Hornbeam”

  1. Karen Thornton

    This was especially interesting to me because I just put my American Hornbeam into a bonsai pot this afternoon. It came to me in a plastic nursery pot that had been cut in half and had very little soil. Many roots were bare, so I watered it and wrapped a moist towel around it. I kept the towel moist until my pot arrived. Being new at this, I don’t know if I did the right thing or not.
    It had a lot of very fine, hair-like roots that I trimmed slightly so they were more even and three 1/2 – 3/4″ roots. One of the larger roots was a couple inches longer than the other 2 and wouldn’t sit in the pot well, so I cut it back about an inch. I hope I haven’t hurt it. I would appreciate your thoughts on what I did. I would send you a picture of the finished product if you can tell me where I should send it.
    Thanks for the article Zach.

  2. Zach Smith Post author

    Karen, hornbeams usually can take pretty hard root-pruning so it’s not likely you caused any damage. Just be sure to not do anything more to your tree (above ground) until after the first flush of growth this spring, and leave the roots undisturbed until at least next year.
    You can email me your picture directly.

  3. tim

    I’ve been looking for elm un my area and accidentally came across some hornbeam. I collected a few in early October because there was a construction project about to break ground and they would have been discarded. 2 of the 3 have swollen buds about to open but we are expecting our first frost this weekend. What would you do in my position? They both have nice movement and taper so I really hope they make it. Do u know of any hornbeams being successfully collected this time of year? Your expertise has been indispensible to my success in bonsai thus far. Thank you.

    • Zach Smith Post author

      Tim, I haven’t tried collecting hornbeam this time of year but wouldn’t hesitate if they were doomed otherwise. I think it’s a good sign they’re trying to push buds; that means they haven’t suffered sap withdrawal. What I’d do is simply give them winter protection just like any other tree except a little more so assuming the new roots won’t be as hardened off as your other trees’ are. You may be pleasantly surprised come spring. Good luck with them!

  4. Matt

    What time of the year would you recommend collecting hornbeams (Atlanta-ish area)?

    Thanks so much! Super excited to find this info, I honestly didn’t think I was going to be able to do much yamadori around me but between the oaks, hornbeams, and sweetgums I think I may actually have some options!

  5. Luke Omohundro

    I live in Bozeman Montana–can get very cold here in the winter. I have successfully over-wintered bonsai by burying them in a protected area near the house Foundation. How hardy are American Hornbeam? do you think it could over winter here the way I described above?

  6. Jon Miner

    I collected a Hornbeam seedling (we call them Ironwood) here in Michigan and stuck it in a small pot in our vegetable garden over the summer. It’s still alive and I am now ready to re-pot it with plans of bringing it indoors for the winter. I hope to make it into a bonsai eventually. I have many questions. What type of soil? What type of pot? Should I trim the roots yet? What conditions should it live in over the winter? I have a cool basement that doesn’t get much light. Thanks!

    • Zach Smith Post author

      Jon, hornbeam is a strictly outdoor species and should not be brought inside during winter. The exception is that you can use an unheated garage during really extreme cold weather. The best way to overwinter hornbeam where you are is in a cold frame, mulched over if need be to provide some insulation. Also, I don’t recommend repotting hornbeam at this time of year; slip-potting is okay, but avoid root disturbance. That means no root-pruning. As for soil, you can make a good mix by using half and half pine bark mulch and Turface or a similar inorganic. This will work for a wide variety of species.

  7. Pappy Doyle

    Sir: A friend of mine gave me a small 18″) hornbeam he had collected in North Carolina and kept in the Tidewater area of Virginia. I live in Tucson, Arizona, and wonder about the low humidity and high temps this summer. I have a porch that gets good morning light, and can shade it during the 110° noon and afternoon. Is there more I should be doing?

    • Zach Smith Post author

      Your best bet is to acquire a humidity tray to set the tree on, since you don’t have much humidity in your climate. Hornbeam in Tucson will be a challenge, so do keep it out of the high heat.


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