Black oak is a member of the red oak group, and it is one of the most valuable plants around for hosting caterpillars. It generally grows 50 to 60 feet tall and wide with an irregular form. Its common name refers to its nearly black bark, while another common name, yellow bark oak, refers to the yellowish-orange inner bark. The dark trunk and branches are a pleasing contrast with velvety red buds, deeply lobed green leaves, golden catkins, and brilliant orange and red foliage in autumn. Medium-sized, large-capped acorns adorn the tree every two years--food for wildlife and humans, if correctly prepared. A unique feature of black oak that distinguishes it from others in the red oak group is the fuzzy look and feel of the leaf undersides and buds, thus its Latin name velutina, which means “fleece or woolly down.”
Black oak is found throughout almost all of Ohio, most often in the foothills of Appalachia and sandy ridges near Lake Erie. It also grows in a wide variety of upland medium-dry sites, flatwoods, and savannas. Often grown as a shade tree in larger spaces.
Plant Characteristics:
Grows 50-60’ tall and wide.
Thrives in full sun, but tolerates part sun.
Prefers moist, rich, acidic, well-drained soil but tolerates extremely poor, dry, sandy, or heavy clay soils because its long tap root allows it to survive difficult conditions.
Drooping male catkins fertilize small female flowers on the same tree in mid-spring. Fruits take two years to develop into mature acorns, which ripen and turn brown August to October. Scaly cap covers almost half of the nut.
In early spring, velvety red leaves emerge, turning shiny green on the surface with clumps of hairs on the undersides. Leaves are typically 4-8” long with 5-9 lobes of varied shapes that have bristles on the sharp tips. Late fall color ranges from orange-yellow to red.
Trunk may be large in maturity, up to 3 ½’ around. Immature bark is smooth, while mature bark has vertical ridges with horizontal grooves that give a blocky appearance.
Wildlife Value:
Host plant to 477 species of Lepidoptera larvae, including the sleepy duskywing, spun glass slug moth, rosy maple and great leopard moths. Also a host for the larvae of the Northern walkingstick (stick insect). The acorns provide food for numerous wildlife species, including songbirds, squirrels, mice, voles, white-tailed deer, and wild turkeys. Trunk cavities provide nest sites for screech owls, tanagers, hawks, woodpeckers, tree squirrels, chipmunks, flying squirrels, deer, foxes, white-footed mice, and raccoons.
Medicinal, Edible, and Other Uses:
Native Americans used black oak to treat indigestion, chills, fevers, respiratory problems, and sore eyes. It was also used as an antiseptic and to induce vomiting.
Acorns, which supply eight essential amino acids, have been eaten as a staple food on four continents. They contain digestive inhibitors (tannins and phytic acid) that prevent absorption of the nut’s minerals. Native Americans soaked, sprouted, or fermented the nuts to reduce the tannins and phytic acid.
Black oak is used for firewood more than any other oak wood, and to make furniture, flooring, pallets, boxes, railroad ties, and mine timbers. The inner bark is used to make a yellow dye called quercitron.