Blog Post

Tree of the Month: American Hornbeam

The American hornbeam (Carpinus caroliniana) has a variety of alternate names – “Blue Beech,” for the color of its bark, and “Musclewood” for the muscle-like ripples in the trunk. It’s a stately yet humble tree native to the understory of woods and shady areas along streams. It is a member of the birch family and has finely toothed leaves reminiscent of those of birches, though generally smaller in size.

An interesting feature of most trees in the birch family is the cylindrical, pendulous flowers with the special name “catkin.” The male catkins (which produce the pollen) of the American hornbeam differ from those of its cousin, the hophornbeam, in that they form in the spring as opposed to the previous fall. So if you see fresh catkins on a tree in the fall or winter, you can be sure you are NOT looking at an American hornbeam, but rather something else in the Birch family. The female catkins, when pollinated well, will develop into a long chain of 10 to 30 winged seeds that are a unique and aesthetically pleasing feature. The American hornbeam has a wide range, from Quebec, Canada down south to Florida and from the east coast west to Minnesota and Texas.

The American hornbeam and hophornbeam are not even in the same genus and their barks look very different, but they do share a well-deserved secondary name: Ironwood. These two species have some of the densest wood around, and were used for some roles that iron metal fills today. The name, ‘horn’-‘beam’ refers to the wood being as durable and close-grained as an animal horn. Traditionally, they were used for tool handles and heads, wooden cogs, flooring, and golf clubs for their durability, as well as for turned bowls and plates due to their tendency to resist cracking. It is also reported that trying to work hornbeam with sharp tools will dull the tools very quickly, as if you were trying to cut into iron. Because of their density, these trees can make great fire wood if they exist in abundance on a given piece of land.

In a home landscape setting, this tree thrives in shady areas – though with a little pampering and some deep, rich soil, it can be an excellent addition to sunnier areas as well. It reportedly can reach 65 feet in its natural setting but you should expect only around 35 feet or less in a domestic setting, and that much only after many years as this tree naturally grows quite slowly. When allowed to go where they will, American hornbeam grows into a variety of unconventional form, with twists and multiple trunks that can be quite lovely. If trained properly, this species can work well as part of a hedge. A close relative of our tree, the European hornbeam, has been a classic landscape tree for centuries with many cultivars. The American hornbeam has a little more wildness in its blood but is an excellent native candidate for taking an increased role in our cultivated landscapes.

If you stroll long enough along the Rock Creek Park bike path you will certainly encounter a number of American hornbeam specimens – and if you venture into to the woods a little or close to the creek, you can find them in their natural setting. You can also see two planted in front of the Casey Trees office! Stop on by and say hi.

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Flickr credit: intheburg, Sherief Saleh.

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