Quercus palustris, the pin oak or swamp Spanish oak, is a tree in the red oak section (Quercus sect. Lobatae) of the genus Quercus. Pin oak is one of the most commonly used landscaping oaks in its native range due to its ease of transplant, relatively fast growth, and pollution tolerance. Its distinctive shape is considered unique among hardwoods.
Quercus palustris commonly called pin oak is a medium sized deciduous oak of the red oak group that typically grows 50-70’ (less frequently to 100’) tall with a broad pyramidal crown. Upper branches are ascending, middle branches are somewhat horizontal and lower branches are descending. In the wild, the lower branches of this tree are often shaded by other trees, eventually dying and breaking off leaving persistent pin-like stubs, hence the common name. Trunk diameter to 3’. Smooth gray-brown bark usually develops ridging with age. This is a tree of lowlands and bottomlands that is primarily native to the Midwest and mid-Atlantic States. In Missouri, it typically occurs in valleys, floodplains and stream margins, but is infrequently found in drier upland areas (Steyermark). Insignificant monoecious yellowish-green flowers in separate male and female catkins appear in spring as the leaves emerge. Fruits are rounded acorns (to 1/2” long), with shallow, saucer-shaped acorn cups that barely cover the acorn base. Acorns are an important source of food for wildlife. Glossy, dark green leaves (to 5” long) typically have 5 bristle-tipped lobes with deeply cut sinuses extending close to the midrib. Leaves turn deep red in fall. Pin oak is pehaps the most popular commercial oak of eastern North America, having been widely planted as both a street and a landscape tree.