Willow oak is a large, deciduous, graceful tree with a straight, tall, slender trunk and willowlike leaves. The leaves are 5 to 8 times as long as wide, with no lobes or undulations. This species is long-lived and shows moderately rapid growth on good sites. On alluvial soils, the feeder roots are concentrated in the aerated layer above the saturated zone.
Willow oak is monoecious.
Acorn production begins when the tree is about 20 years old. This species produces a good acorn crop nearly every year. Blue jays transport and cache acorns up to several kilometers from the collection tree. Germination is hypogeal. Early height growth of seedlings is moderate.