Quercus phellos

The first surprise of Quercus phellos is that nobody believes they're an oak. The leaves are narrow and untoothed, willow-like, finer than an oak has any right to be, and they turn soft yellow before they fall; only the acorns, small and round and produced by the thousand, give the game away.

There is a small joke folded into the name, too. Phellos is the old Greek word for the cork oak, so Linnaeus reached for the name of one tree to christen another that resembles neither cork oak nor, in fact, an oak at all, but a willow. Native to the bottomlands and moist flats of the coastal plains from Long Island south and well up the Mississippi valley, willow oak has spent the last century becoming one of the great street and shade trees of the South, the reason so many old town squares and college quads are roofed in fine green shade.

They grow fast for an oak, two feet a year when young, into a clean trunk and an open, rounded crown of forty to sixty feet, and they shrug off clay, compaction, and city air. The texture is the seduction: where most oaks read as heavy, willow oak reads as light, almost airy, casting shade without the bulk. The small acorns feed everything, ducks especially.

Plant one and you are planting for the people who will sit under them long after you, which is the only honest reason to plant an oak at all. Use willow oak as a street or avenue tree, a fast shade tree for a large lawn, or a canopy anchor for a park or campus, on moist to average, well-drained ground with room for the broad crown. Pair with other bottomland and street-tough natives, and give the young tree early structural pruning to build a strong, single leader.