Swamp white oak

* Common name: Swamp white oak

* Botanical name: Quercus bicolor

* What they are: Swamp white oak is a long-lived Pennsylvania-native shade tree that’s a good food source for a variety of moth and butterfly caterpillars as well as a good supplier of acorns for small mammals (at least in the years when it produces an acorn crop).

   People benefits include cooling shade in summer and a yellow to orange-gold fall-foliage show. It’s also a solid-enough performer to earn a 2023 Gold Medal Award from the Pennsylvania Horticultural Society as a tree deserving more use in home landscapes.

   The bark of swamp white oak is grayish-brown, furrowed, and somewhat peeling, while the leaves have silvery undersides.

* Size: Give this tree plenty of room because the straight species can grow 50 to 60 feet tall and wide in time. Beacon is a narrow variety of swamp white oak that grows about 40 feet tall but only 15 feet wide.

* Where to use: Although swamp white oak prefers damp, acidic, and even wet soil (it’ll survive occasional flooding), it’s adaptable to the drier conditions and clayish soil that’s common in urban and suburban yards. Grows best in full sun.

* Care: Keep the roots consistently damp the first two to three seasons to establish the roots, then soak deeply once a week in extended hot, dry spells. Fertilizer is usually not needed, especially if you’re fertilizing the lawn nearby.

   Pruning is best done in winter to lessen the odds of oak wilt, which is the tree’s main disease threat. Remove crossing or excess branches, and “limb up” the lower branches if needed to walk underneath.

* Great partners: Turtlehead, golden ragwort, Pennsylvania sedge, foamflowers, and crested iris make good native underplantings that also prefer damp conditions. Barrenwort and helleborus are two other non-native groundcover choices. Summersweet and dwarf winterberry holly are two native, damp-preferring shrub partners.