Quercus laurifolia (swamp laurel oak, diamond-leaf oak, water oak, obtusa oak, laurel oak) is a medium-sized semi-evergreen oak in the red oak section Quercus sect. Lobatae. It is native to the southeastern and south-central the United States, from coastal Virginia to central Florida and west to southeast Texas.
There are reports of the species growing in Pennsylvania and New Jersey, but these probably represent introductions.
Quercus laurifolia is a tree growing to 65–80 feet (20–24 meters) (rarely to 130 feet (40 meters)) tall, with a large, circular crown. The leaves are broad lanceolate, 1–5 inches (2.5–12.7 centimetres) long and 0.5–1.75 inches (1.3–4.4 centimetres) broad, and unlobed (very rarely three-lobed) with an entire margin and a bristle tip; they typically fall just as the new leaves start to emerge in spring.
The acorns, borne in a shallow cup, are hemispherical, 0.35–0.5 inches (8.9–12.7 millimetres) long, green, maturing blackish-brown about 18 months after pollination. Despite their bitter kernel, they are eaten by deer, squirrels and birds. Acorn production is often heavy, enhancing the species' value for wildlife.
The seedlings show embryo dormancy and germinate the following spring after fall ripening; germination is hypogeal.
Swamp laurel oak grows rapidly and usually matures in about 50 years which has led to its wide use as an ornamental. It is host to the general oak-feeding insects but has no serious insect problems. Several species of Curculio weevils infest the acorns.