OTHER COMMON NAMES: BLACKJACK, BARRON OAK, JACK OAK, BLACK OAK
BOTANICAL NAME: Quercus marilandica KWEAR-cus mar-ah-LAN-di-cah
FAMILY: Fagaceae (Beech Family)
TYPE: Deciduous shade tree
HEIGHT: 50 to 60 feet
SPREAD: 30 to 40 feet
FINAL SPACING: 30 to 40 feet
NATURAL HABITAT AND PREFERRED SITE: Eastern half of Texas especially in the sandy acid soils. There is a western form of blackjack that grows only to 30 feet and can grow in sand or gravel, clay soils that are only slightly acidic.
IDENTIFICATION INFORMATION: Rounded symmetrical tree with club-like leaves and very dark heavily textured bark. Stiff in overall appearance.
FLOWERS AND FRUIT: Flowers appear with the leaves in the spring as slender hairy yellowish-green catkins 2 to 4 inches long. The fruit is an acorn that ripens in 2 years, either solitary or in pairs.
BARK: Dark brown to almost solid black, broken into rough block-like plates, heavy texture and usually very dark in color.
FOLIAGE: Leaves are simple, alternate, deciduous and club- shaped. Fall color is yellow but not a knockout.
CULTURE: For the most part blackjack oak needs sandy acid soil to survive. Does not do well in the black and white soils of north Texas. It is drought tolerant and needs very little fertilization.
PROBLEMS: Does not do well in the alkaline clay soils.
PROPAGATION: From acorns planted in the soil immediately after releasing from the tree in the fall.
INSIGHT: Blackjack oak is said to indicate poor soil areas. It is rarely cultivated because it is difficult to transplant.