Quercus ellipsoidalis aka Hill's Oak

Quercus ellipsoidalis is a deciduous tree in the beech family. Its common names include northern pin oak and Hill’s oak. It belongs to the red oak group. Its native range covers southwest Ontario and north-central and east-central America. In the United States, it grows around the Great Lakes. Wild trees grow in dry woods, sandy hills, and prairies.

In gardens, trees reach about 50–70 feet [15–21.34 metres] tall. Their spread can reach 60 feet [18.29 metres]. RHS reports taller trees reaching 98 feet [30 metres]. The crown can be rounded, oval, or uneven in shape. Upper limbs rise, while lower limbs bend toward the ground. Shaded lower limbs can die and leave short, pointed stubs. Young bark is gray-brown, with some smooth strips. Older bark grows dark, with broad ridges and narrow grooves. The inner bark has an orange tint. Red-brown twigs bear clusters of pointed buds at their tips.

The leaves grow in an alternate pattern along the twigs. Each leaf has deep cuts between its bristle-tipped lobes. Leaves measure about 3–7 inches long and shine green above. Their pale undersides may have small hair tufts near veins. In fall, the leaves turn crimson to purple. Small yellow-green flowers appear as the spring leaves unfold. Male flowers hang in catkins; female flowers form short spikes. Both flower types grow on the same tree. The oval to nearly round acorns ripen in fall. They need two years to mature. Their cups cover about half of each nut.

Grow this oak in full sun and well-drained soil. It accepts sand, loam, and clay, with good drainage. Acid soil is the safer choice for garden planting. Alkaline soil can cause severe leaf yellowing and damage. Steady moisture suits it, though it also tolerates dry soil. Sources rate it for USDA zones 4–8 and UK H6. It needs little routine care and makes a large shade tree. Lawns, parks, and streets offer uses where space allows. It also attracts birds.

Possible pests include aphids, borers, caterpillars, and leaf miners. Oak gall wasps, scale, and nut weevils may also occur. Diseases include oak wilt, powdery mildew, and honey fungus. PFAF lists cooked seeds as food after removing bitter tannins. This food use does not make raw acorns safe. RHS warns that eating the plant can harm dogs. The hard wood serves for floors, furniture, and indoor finishes.