American Hornbeam (Musclewood)

Size, growth and what to expect

American hornbeam adds 8 to 10 feet of height in ten years, about a foot a year. Our growth estimator models it at the same slow rate in its youth on an average site. Trees top out at 15 to 20 feet in Canada and 25 to 35 feet in the South, with a crown about as wide as the tree is tall. Trees are short-lived, typically about 100 years and seldom past 150.

The first seed comes at about 15 years, with a large crop every 3 to 5 years. Catkins open in April and May, and the ribbed nutlets ripen in October, each hanging under a three-lobed leafy bract about an inch long. Songbirds, grouse, turkeys and squirrels take the seed, buds and catkins. The bark on older trees is smooth slate gray and fluted like a flexed arm, which is where the name musclewood comes from.

It grows wild across most of the eastern United States, from southern Ontario and Quebec to eastern Texas and the Ozarks.

How to grow American Hornbeam

American hornbeam thrives in shade. It takes full sun as well if the soil stays moist, and it is untroubled by wet ground or spring flooding. Plant it on a streambank, in a low corner or beneath oaks. At full size it needs 15 to 20 feet from a building and from other trees.

Set out dormant bare-root saplings in early spring, which suits hornbeam better than fall planting. Dig a broad, shallow hole, position the root flare at the surface, and refill with unamended soil. Water thoroughly, then mulch a ring three inches deep that does not touch the trunk. Pick the seed while the nutlets are still greenish and sow it outdoors that fall, a quarter inch deep under mulch. Seedlings come up the next spring. Seed gathered brown and dry needs two to four months of cold, damp storage, and some of it waits until the second spring.

Musclewood is slow to settle in, so water it weekly through the first summer and in dry weeks for two more years. Deer and rabbits both damage young hornbeams, so use a wire guard until the trunk is two inches thick.

Male and female catkins appear together on the same tree and the wind carries the pollen, so one tree sets seed alone. Expect little top growth for the first few years while the roots establish. Fall color is orange to red and strongest in sun. Prune in summer if you must, since late winter cuts can bleed sap.