Seeds are egg-shaped, winged and less than 0.1 inches long. The bark is gray and scaly on young trees, later becoming deeply furrowed and ridged. Hemlock bark was once an important source of tannin. This species is native to the northeastern US and southeastern Canada and will grow well in Iowa only when planted in cool, moist, sheltered positions in eastern and central Iowa. The location of this particular group of trees on the ISU campus is ideal, mimicking the microclimate of the cool, shaded, moist valleys and canyons where these trees would naturally occur.
Hemlocks are fast-growing, but require abundant moisture.
The leaf litter formed by fallen leaves produces, over the years, an acid soil which may discourage competition from some plants. Needle blight is a disease that may cause some leaves to turn brown and die, but this species is subject to very few diseases in Iowa. It is often knotty due to the persistent branches and is occasionally used in rough, general construction and for pulp. It sparks and pops considerably when burned and is therefore not suitable for use as firewood. Forming a dense, evergreen cover, the eastern hemlock is an important shelter tree in winter for white-tailed deer, ruffed grouse and wild turkey.