The arboretum includes over 185 cultivars of American holly species. American holly tea does not contain caffeine. Other trees present are American beech, swamp white oak, and American holly. Leaves from the American holly can be used to make a tea-like beverage. The European holly is smaller than the American holly, but closely resembles the American holly. The American holly are particularly large, reaching in diameter and tall. Understory shrubs include flowering dogwood ("Cornus florida") and American holly ("Ilex opaca"). American holly ("Ilex opaca"), a broadleaf evergreen tree, is common.