北美灰橡分佈在較乾燥的棲地時,多會以多莖灌木的形式生長,但在降雨充足的情況下,將會長成中等大小的喬木,樹高約20公尺(66英尺),具有不規則扭曲的樹冠。樹幹直徑可達60公分(2.0英尺),樹皮為淺灰色並呈現龜裂狀。幼枝粗壯,呈淺紅棕色,覆蓋著淺灰色絨毛。葉互生,具革質,長卵形,全緣或部分葉緣具粗鋸齒狀,葉面呈灰綠色而葉背有纖毛,可能在冬季乾旱時掉落。雄花為黃綠色柔荑花序,而雌花為生長於葉腋的穗狀花序,春季與新葉同時出現。殼斗(英语:Calybium and cupule)有鱗,佈滿纖毛,[2][3][6]
^ 3.03.13.23.3Pavek, Diane S. Quercus grisea. Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory. 1994 –通过https://www.feis-crs.org/feis/.
^Quercus grisea. County-level distribution map from the North American Plant Atlas (NAPA) (Biota of North America Program (BONAP)). 2014.