Blackjack Oak
Quercus marilandica Muenchh.

Blackjack Oak: Full Size

Mature Size: 20 to 30 feet in height and 6 to 12 inches in diameter; rarely may reach 50 feet in height.

Form: Short trunk and crooked, twisting branches forming an uneven crown; small, stiff dead branches commonly present.

Habitat: Most common on heavy clay or dry gravelly or sandy upland soils.

Leaves

Blackjack Oak: Leaves

Alternate, simple, 4 to 8 inches long, leathery, usually broader at the end than at the base, with 3 large lobes; often described as "bell-shaped;" undersides brownish or orangish and quite hairy.

Flowers

Males in 2 to 4 inch long hanging catkins; females small, single or paired.

Fruit

Blackjack Oak: Fruit

¾ inch oblong acorn, often striped, half covered by a thick, scaly cup.

Bark

Blackjack Oak: Bark

Rough, very dark (often nearly black), broken into small, hard rectangular blocks.

Twigs

Thick, dark brown, with some hairy tufts; buds reddish brown, ¼ inch long, sharp, angled and fuzzy.

Values and Uses

Blackjack oak is not valuable as a timber species, but it is sometimes used for charcoal, firewood and occasionally for railroad ties. The acorns are eaten by wildlife.

Did You Know?

The presence of blackjack oak is said to indicate poor soil.