Tree Leader Training American Hornbeam - Ask Extension
Hello,
I planted an American Hornbeam in my yard two or three years ago. When I planted it, it was about two feet tall and did not have the best st...
Knowledgebase
Tree Leader Training American Hornbeam #890500
Asked December 04, 2024, 10:51 AM EST
Hello,
I planted an American Hornbeam in my yard two or three years ago. When I planted it, it was about two feet tall and did not have the best structure. Now its about 8 feet tall, the majority of the growth happening this year. It seems to have fixed the structural concerns I previously had but has now created new ones.
I am wondering if I should do something to train a central leader. As you can see from the pictures, the tree sort of splits horizontally on top. I was thinking I could maybe cut one of the top horizontal branches and/or tie a horizontal branch to bamboo to encourage it to grow vertically.
Also wondering if it would be best to just leave it alone and see if the tree can sort itself out. However, the tree is about 20-25 feet from my home so I would like it to have good branch structure and not be a hazard.
I would really appreciate some advice. Thanks in advance!
Baltimore County Maryland
Expert Response
European Hornbeam (Carpinus betulus) doesn't develop a central leader by nature, but we're finding less information about American Hornbeam (Carpinus caroliniana). References imply that it might not form one either, or at least not at this young of an age, but that trees can be manually trained to form a leader if the gardener wants. How necessary that would be for the long-term health or stability of the tree, though, we don't know. Our guess is that it's probably not necessary, especially given the tree's comparatively small stature when mature and its current distance from the house, but you might be able to consult a certified arborist or licensed tree expert to get their opinion based on any experience with American Hornbeams in particular. Anecdotally, we've not seen them become a problem in terms of dropping limbs or frequently succumbing to storm damage, but we don't have the level of tree structural development training that arborists have, and to be fair, American Hornbeam is unfortunately under-used in home landscapes so there aren't many examples of mature trees in residential yards for comparison.
Pruning growth tips encourages branching-out from the point of the cut, so it would potentially make the cut branch denser over time (supporting more secondary branches and their foliage), though at this age, most branches on a tree's trunk are still comparatively temporary, as they tend to naturally die off and be shed as the tree matures and gets taller. One technique to avoid the development of codominant stems (dual leaders) is to shorten one of them while it's still quite young, though how often that succeeds we don't know; it might depend on tree species as well as age. Based on your photos, the tree might still develop new growth in the next year or two at the point where a leader would usually be found (since it's exposed to lots of sun with no canopy shade directly over it), and develop that new shoot into a more upright growth point that becomes dominant (even if the two topmost branches currently oriented more horizontally aren't trimmed)...but that's hard to predict.
Miri
Pruning growth tips encourages branching-out from the point of the cut, so it would potentially make the cut branch denser over time (supporting more secondary branches and their foliage), though at this age, most branches on a tree's trunk are still comparatively temporary, as they tend to naturally die off and be shed as the tree matures and gets taller. One technique to avoid the development of codominant stems (dual leaders) is to shorten one of them while it's still quite young, though how often that succeeds we don't know; it might depend on tree species as well as age. Based on your photos, the tree might still develop new growth in the next year or two at the point where a leader would usually be found (since it's exposed to lots of sun with no canopy shade directly over it), and develop that new shoot into a more upright growth point that becomes dominant (even if the two topmost branches currently oriented more horizontally aren't trimmed)...but that's hard to predict.
Miri
