The University of Arkansas System Division of Agriculture does not promote, support or recommend plants featured in 'Plant of the Week.' Please consult your local Extension office for plants suitable for your region.

• Blackjack Oak Tree Florida
• Blackjack Oak Tree Identification
• What Is A Blackjack Oak Tree Stands

Blackjack Oak
Latin: Quercus marilandica

This interesting oak species is often an associate of the better-known post oak, but blackjack oak is even more drought tolerant and survives on some of the toughest sites around. Blackjack oak is a small to medium-sized tree which can grow to heights of 50 feet, but is usually much smaller. The trunk is often gnarled, with a diameter of up to 1 1/2 feet. The crown is rounded, with lower branches hanging downward. Blackjack oak grows on poor, dry, and rocky or sandy soils in Illinois. Quercus marilandica, the blackjack oak, is a small oak, one of the red oak group Quercus sect. It is native to the eastern and central United States, from Long Island to Florida, west as far as Texas, Oklahoma, and Nebraska. There are reports of a few isolated populations in southern Michigan, but these appear to represent introductions.

This summer’s drought has been tough on trees. The drive between Fayetteville and Little Rock is punctuated with whole hillsides of brown and seemingly lifeless trees.
While these trees - mostly oaks, hickories, dogwoods and elms - look bad from a distance, most will survive the rigors of the 2000 drought without much problem. Summers like this help one appreciate the really tough trees such as the blackjack oak.
A kid I knew in my youth was scrappy and always getting into fights. His favorite saying was, 'When you’re ugly you gotta be tough.' Mother Nature has applied this simple truism to the blackjack oak because it is one ugly, but tough tree.
Blackjacks are found throughout most of the eastern woodlands, occupying sites with soil too poor or dry for oaks with more stature and substance to flourish. It was one of the few tree species to venture onto the Great Plains before white settlement, occupying a region from central Texas northeast through Oklahoma known as the cross timber region.
The blackjack is a small, gnarly tree usually under 35 feet tall with a round crown and leathery, three-lobed leaves. It is a member of the red oak tribe and has the characteristic leaf spine at the end of each lobe. The leaves hang on the tree through the winter to be pushed off by new leaves the following spring. It’s trunk is often deeply furrowed and black, giving it a brooding wintertime appearance.
The Rodney Dangerfield of oaks, blackjacks are given but one use - firewood - by most authors who seem overly hung up on the notion that all oaks reach the pinnacle of their glory at the saw mill.
It might be instructive to speculate on the long term effects of this summer’s drought on the survival and health of the forest. As bad as the trees look, most will survive the drought because they have been forced into an early dormancy to conserve water.
Unfortunately, that is not the end of the story. The oaks of our eastern forest are systemically infected with a fungus called Hypoxylon canker - sort of the athlete’s foot of the oak kingdom.
Survey work conducted by Dr. Pat Finn at the UofA following the severe drought of 1980 showed that about 80 percent of the oaks of northwest Arkansas have this systemic infection. This fungus is usually benign and does no apparent harm, but droughts cause it to flare up. Certain trees -- with no discernable pattern -- are killed by the multiplying hyphae of the fungus as it produces its spores on fungal mats under the bark of the tree. These fungal mats push the bark off which accumulates at the base of the tree like a rain of deadly dandruff.
For the health of the forest, Hypoxylon is a beneficial fungus because it thins the stand of trees. In 1980, the disease killed about 12 percent of the oaks in some areas, thus allowing the survivors more opportunity to obtain water.
Unfortunately most of us that build our homes in the woodland have difficulty taking the long view on ecology when the tree in front of our house is the one that dies. About all that can be done to ward off the effects of this problem is to keep the drought at bay by watering before conditions become too severe.
Blackjacks are not in the nursery trade and many who have them on their property treat them with little respect. But, before dismissing this tough tree as a scrub oak and relegating it to the woodpile, reflect on its toughness and adaptability under adverse conditions.

By: Gerald Klingaman, retired
Extension Horticulturist - Ornamentals
Extension News - September 22, 2000

1. 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.
2. Around here in Oklahoma, the hills are lousy with blackjack oak. Not sure if it is the same tree you have there, the ones around here are lucky to get 20 feet tall. It is mostly a trash tree, decent firewood, but not a two-foot long straight piece to be found.

Blackjack Oak Tree Florida

Blackjack Oak Tree Identification

What Is A Blackjack Oak Tree Stands

The University of Arkansas Division of Agriculture does not maintain lists of retail outlets where these plants can be purchased. Please check your local nursery or other retail outlets to ask about the availability of these plants for your growing area.