Gerald L. Klingaman
Plant Common Name
This entry has yet to be reviewed and approved by L2G editors.
A perfectly shaped oak tree for an old college campus or stately field, blackjack oak has elderly character. It develops a relatively short, stout trunk with chunky dark gray bark and forms an irregularly rounded canopy with pronounced, somewhat gnarled branches. Dead branches persist due to the resilient strength of the wood and must be pruned off to keep trees looking their best. This deciduous oak is smaller than most species and native to areas across the eastern United States, from New York down to Florida and across to Texas. It is most commonly found growing in upland savannas and forests adjacent to grasslands where soils are well-drained and have moderate to poor fertility. Blackjack oak is in the red oak group (section Lobatae), so its leaf tips are pointed rather than rounded and its acorns have imbricate rather than knobby caps.
The leaves emerge in spring and are thick, leathery and glossy deep green. Each is shaped like a duck's foot or wedge with three or four rounded lobes that flare towards the tip. Leaf undersides are lighter green and covered in orange-tan hairs. The yellowish male flowers appear in pendent clusters called catkins just before the leaves emerge in spring. New leaves are coral-red when they first unfurl. Shortly after, reddish female flowers bloom at the base of young leaves and capture pollen from the male flowers, which is carried by wind. The oval acorns are light brown, sometimes striped, and half-covered by scaled, hairy caps. In autumn, the leaves turn rusty orange and yellow.
The slow-growing, resilient blackjack oak thrives in full sun to partial shade and acid to neutral soil with good drainage. This tree has a deep taproot, which allows it to draw up water in dry summers, but it does not transplant well, so once it's planted it cannot be moved. This is a beautiful tree for large landscapes or parks. It is also ideal for native gardens. Its acorns are eaten by many wild birds and mammals. In fact, its acorns are one of the most preferred by fox squirrels.
AHS Heat Zone
9 - 3
USDA Hardiness Zone
5 - 9
3b, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17
Full Sun, Partial Sun
45'-50' / 13.7m - 15.2m
30'-40' / 9.1m - 12.2m
United States, Mid-Atlantic United States, Southeastern United States, Central United States, South-Central United States, Texas
Drought, Soil Compaction
Drought Tolerant, Average Water
Spring, Summer, Fall, Winter
Screening / Wind Break
Sharp or Has Thorns