Volume XXXIII Number 1 Page 15

Whether it’s called ironwood, musclewood or its given name, American hornbeam is one tough tree. It’s this toughness that helped it receive the 2008 Georgia Gold Medal for deciduous trees.

Adaptability to a wide variety of soils and growing situations is one of the criteria a plant must meet before being elevated to gold medal status. The American hornbeam (Carpinus caroliniana) fits this to a tee. This native tree grows from Nova Scotia in the north to Florida in the south to Texas in the west, or in hardiness zones 3 to 9.

In its native habitat, American hornbeam is most often found along rivers and streams in the rich, moist soils of the floodplains, but it also adapts to dry upland sites. In the wild, it grows in the dense shade of taller trees, but it can adapt to full-sun spots. These characteristics make it a very versatile tree for a wide variety of landscape situations.

An interesting use for American hornbeam, other than as a specimen tree, is to plant it as a hedge or screen plant and to shear it into a formal box-like shape. Although this greatly increases the maintenance requirement of the plant, it adds an interesting, somewhat European element to the landscape.

American hornbeam is also an excellent alternative to Bradford pear, which has a problem with weak wood and limb breakage during storms. It has a broad, oval growth habit, similar to that of Bradford pear, and reaches 30-40 feet in height and is 30 feet wide at maturity. Its dense foliage casts cooling shade in summer then brightens the autumn landscape with shades of yellow, orange or red.

The tree is sometimes called ironwood, a name used to describe its very hard wood and its dark-red to brown colored twigs. Early settlers valued the durability of the wood and used it for split-rail fences and fence posts. American hornbeam is also called musclewood due to its smooth, slate-gray bark that becomes ridged with age, looking similar to the rippling arm muscles of a well-conditioned athlete.

American hornbeam bears separate male and female flowers on the same tree. In late summer, the female flowers become distinctive clusters of winged nutlets that hang down from the twigs on short stalks.