American hophornbeam

American hophornbeam, more commonly known as ironwood, is an small, slow-growing, short-lived, deciduous tree that rises on a single trunk. It is considered a weed tree. In Minnesota mature trees are usually 25′ to 40′ tall and 6″ to 12″ in diameter at breast height.

The crown is broad and rounded or cone-shaped.

The trunk is erect, often crooked, and distinct almost to the top of the tree.

The bark on young trees is smooth and chestnut brown, quickly becoming gray and rough. On mature trees the bark is grayish-brown and is broken into short, narrow, vertical strips that are loose at both ends. The strips often spiral somewhat around the trunk. They are fibrous and easily rub off.

The branches are long, slender, and spreading.

The twigs are slender, reddish brown, zigzagging, and hairy.

The buds are egg-shaped, pointed, slightly hairy, and greenish brown with green scale tips. They spread away from the twig.

The leaves are deciduous, alternate, and simple. They are narrowly egg-shaped or elliptic. usually widest near the middle, 2″ to 5″ long, and 1″ to 2″ wide. They are rounded or shallowly heart-shaped at the base. They usually taper to an abrupt, narrow point at the tip with concave sides along the tip. Sometimes they taper gradually to a point at the tip with straight or concave sides along the tip. The upper surface is dark yellowish green and hairless. The lower surface is the same color but hairy, felty and soft to the touch. The veins are straight and parallel and end in a tooth. The margins are sharply toothed, often doubly toothed, from the tip to the base. In the fall the leaves turn dull yellow. Dead leaves tend to remain on the tree throughout the winter.

Male and female flowers are in separate clusters on the same tree. Male inflorescences are dense, drooping, 1″ to 2″ long catkins in groups of 2 or 3 at the ends of the twigs. In the winter they are short, stiff, and erect. Female inflorescences are in loose, elongated clusters at the ends of new shoots.

The fruits are small, 3 ⁄16″ to 5 ⁄16″ long, flattened, nuts enclosed in a flattened, egg-shaped, about 13 ⁄16″ long, inflated, papery sac. The fruit clusters are 2″ to 4″ long, have 4 to 10 sacs each, and resemble hops.

25′ to 40′

The champion ironwood in Minnesota is on private property near Wells, in Faribault County. In 1998 it was measured at 40′ tall and 125.5″ in circumference (39.9″ in diameter), with a crown spread of 58.5′.

Green

Moist. Upland deciduous forests, well-drained floodplains. Shade tolerant.

April to May

Ironwood leaf gall maker (Eriophyes sp.) creates a small, reddish, smooth, pocket gall on the upper side of the leaf and a small tuft of hairs on the lower side.

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30.

Native

Common

Eastern hophornbeam, Ostrya Virginiana, growing wild in White's Woods Park, Freeborn County, MN, late November 2016

Trunk

Bark

This understory species tends to retain withered, peach-colored leaves into winter, similar to young American Beech

Tree

Bark

Bark

Leaves

Infructescence

Ostrya virginiana
Blake C. Willson

Ostrya virginiana
UF/IFAS WFREC

Trees with Don Leopold - eastern hophornbeam
ESFTV

Hop hornbeam (Ostraya virginiana)
stjoecrk

Luciearl
6/26/2024

Location: Lake Shore, MN

Location: White's Woods County Park, Freeborn County, MN

growing wild in White's Woods Park