What it looks like

Black oak is similar to red oak, but small differences do exist. Black oak leaves typically have fewer lobes (5-7) and deeper U-shaped notches. The upper surface is shiny, dark green, with a yellowish-brown underside that is rough to the touch. The acorns of black oak are 1-2 cm long and equally as wide, with a slightly hairy cup.

Mature bark is square and blocky, where red oak has long, vertical furrows.

Where it is found

Black oak is not a common oak species in Ontario, found in locally abundant populations in southern Ontario, concentrated around Lake Erie and Lake Ontario. In Ontario, it has become associated with remnant areas of dry, tall grass prairie sites, but it can grow on heavier soils.

Planting Tips

  • Size: Up to 20 m
  • Moisture: Moist to dry
  • Shade: Intolerant of shade, requires full sun
  • Soil: Adaptable

Whenever possible, try to collect seed from sites that match the seed zone and site conditions you will be planting into. Some species may be able to adapt but these seedlings will be best adapted to start with.

Did you know?

Black oaks are tolerant of low-intensity grass fires, which enable these trees to survive in tall grass prairie communities.

Black oak has a large taproot that makes it difficult to transplant and hard to find at native nurseries. It does not like to compete with other tree species.

Image credits

  • Tree: Natural Resources Canada, Canadian Forest Service
  • Leaf: Steven J. Baskauf
  • Bark: Keith Kanoti
  • Acorn: Back yard nature