Ohio Trees

Bulletin 700-00

Tsuga – Hemlock

Hemlocks are evergreen trees with cinnamon-red, furrowed bark and horizontal, pendulous branches. Buds are small, globose, and not resinous. Leaves are spirally arranged, usually in two ranks. Needles are about 1/2 inch (13 mm) long with a linear outline. Flowers are monoecious and the fruit is a small cone (less than an inch) with few scales and is showy in the fall.

Key To Tsuga Species

1. Its dark green leaves are flat and arranged in two planes with white, stomatic bands on the underside of the needles. Twigs are only slightly roughened by persistent leaf bases. Branches are long, slender, and often pendulous. The tree forms a broad, pyramidal head.

Tsuga canadensis–Canada Hemlock

Description of Species

Canada Hemlock–Tsuga canadensis

The hemlock is a large timber tree attaining heights of more than 100 feet with trunk diameters of 2—4 feet. The tree occurs along streams and cool slopes in eastern Ohio, along the lake in Lorain County, and southward to Adams County along the Ohio River. It is also found growing native in Green and Auglaize counties. In the Hocking Hills area, the hemlocks reach the zenith of grandeur and beauty. In this scenic area, growing out of the cool ravines and deep valleys, several specimens tower above the sandstone walls 135 feet in height and 41/2 feet in diameter.

The leaves are 1/3—2/3 inches (8—17 mm) in length, oblong, dark green, and lustrous on the upper surface and whitish beneath. Although the needles are spirally arranged, they appear to be two-ranked on the stem. Needles normally fall during the third year. The cones are oblong, about 3/4 inch (2 cm) long, and light brown in color.

Flowers are monoecious and bloom in May. Fruit is a small cone less than an inch long with only a few scales. The cone scales are broadly ovate and are as wide as they are long. The seed is small and winged, maturing in the fall and dropping during the winter.

The hemlocks' horizontal or ascending branches and drooping twigs form a pyramidal crown. This makes it one of our most handsome and desirable evergreen trees for shade and ornament in Ohio. Unfortunately, the tree is site-demanding and difficult to grow where it is not native. Two exotic insects, including a scale insect and an adelgid, have been introduced and are destroying native stands in the northeastern United States.

The wood is light, soft, not strong, brittle, and splintery. It is used for coarse lumber and paper pulp. The bark on old trunks is cinnamon-red or dark gray, and divided into narrow, rounded ridges.

Canada Hemlock