The American hornbeam grows natively in eastern North American and can be found from Maine to Minnesota and as far south as Texas and Florida. This shade tree prefers moist, acidic soil and produces dark green summer leaves that turn a variegated orange in the fall. Come winter, the blue-grey bark creates a beautiful contrast to the snow in northern climates. The hornbeam is a great tree to add to any backyard landscape since it's medium in size and pest and disease resistant.
American Hornbeam Names
The American hornbeam is scientifically referred to as "Carpinus caroliniana" and is part of the Betulaceae (or birch) family. Arborists and cultivars also call this tree blue beech, muscle beech, water beech, muscletree, or musclewood. The name "musclewood" refers to the tree's characteristic bark that looks like a flexing muscle. "Ironwood" describes to the tree's strong wood which rarely cracks or splits, making it useless in woodworking.
American Hornbeam Characteristics
American hornbeam grows naturally in the understory of forests, making it a medium-sized variety suitable to residential landscapes. This species will top out at about 20 to 35 feet tall. The leaves of the hornbeam are medium in size (2 to 5 inches long), are blue-green in color, and elliptical in shape. In the fall, this tree rewards growers with a display of leaves that varies from yellow to orange and purple to red.
The hornbeam produces a nutlet surrounded by a bract. Over the course of the season, several nutlets and bracts become stacked, creating a fruit cluster that dangles off the limbs.
American Hornbeam Growing Tips
American hornbeam is suitable for gardeners in USDA Plant Hardiness Zone 3 and can adapt to a wide variety of light conditions, including full sun to full shade. The American hornbeam thrives in moist or wet soil that is acidic, although it can tolerate slight alkalinity. And while this highly adaptable species can withstand some flooding, the tree has a hard time dealing with drought conditions.
For best results, start American hornbeam from seed on site or select a young tree from a reputable nursery. Plant American hornbeam in the fall, as the seedlings need light shade to propagate. This species also needs regular watering during the dry season. Installing drip irrigation for summer maintenance works great. Other than providing regular watering, this tree is relatively low maintenance. However, it can be difficult to transplant due to its expansive root system.
American Hornbeam Design Tips
American hornbeam looks gorgeous in all seasons. And while it's a slow grower (it can take decades for this tree to reach its maximum size), this tree could cause crowding problems for neighboring trees down the road. Pair it with medium sized evergreens, making sure to leave ample growing space for each species. You can also use an American hornbeam tree as the focal point in a perennial garden by surrounding it with complementing flowers and mulch. That way, it won't outcompete other trees.
Maintenance and Pruning
If you'd like your hornbeam tree to have a single trunk with foliage growing above, make sure to prune it to have only one central leader. This type of tree can form multiple trunks if left to its own devices. You can also prune this species to create a formal hedge or living fence. This works well for town residents wanting privacy without the eyesore of a head-high fence. Regular shearing will be necessary to maintain the shape.
Pests and Disease
American hornbeam is extremely tolerant of both pests and disease, so problems rarely arise. However, hornbeam trees can still develop cankers and can present with leaf scorch or leaf spots. Proper maintenance and appropriate water amounts should prevent this. Rarely, hornbeams rarely suffer insect infestation. But when they do, maple mealybugs and two-lined chestnut borers are usually the culprits.