Swamp white oak (Quercus bicolor) is a medium-size deciduous tree with a short trunk and a rounded crown. The tree is native to Missouri and the Chicago region and likes to grow in wet areas along rivers and lakes. The lobed leaves of the Swamp white oak are dark green on top with a silvery-white underside. Especially young trees have a striking peeling bark. Acorn fruits mature in the fall when the tree colors to a golden yellow. The species was named by Karl Willdenow in 1801 in reference to the two-colored autumnal leaves.
Common name: Swamp White Oak
Scientific Name (family and order): Quercus bicolor (Fagaceae, Fagales)
Species Origin: Eastern USA. Introduced 1801.
New Jersey Status: USDA Native
Habit: Tree, 50 – 60’ high with an equal or greater spread forming a broad open, round topped crown and a short trunk with drooping lower branches.
Habitat: Zone 4 – 8. Found in the low-lying and more or less swampy regions along stream banks; tree requires acid soil.
Trunk/Stem: Stout to slender, yellowish brown to redish brown, glabrous. Bark flaky, grayish brown, divided by deep, longitudinal fissures into rather long flat ridges. The flaky, scaly gray bark is present on young trees (3 – 5”diameter); this unique feature separates it from Quercus alba.
Leaves: Deciduous, Simple, Alternate. Oblong-obovate, 3 -7” long x 1 ¼ -4’wide; the leaf is broadest toward the tip. Tip acute or rounded; base cuneate; margins coarsely sinuate-dentate with 6 – 10 pairs of coarse, obtuse teeth or sometime lobed halfway to the midrib. Adaxial blade leathery in texture, dark green; abaxial blade whitish tomentose or grayish green and velvety; midrib yellowish. Petiole ½ – ¾” long, yellowish. In autumn leaves turn red and chestnut-brown above and pink below (bicolor).
Flowers: Monoecious. Flowers appear on old or new growth; staminate catkins pendent and clustered; its flowers comprise a 4 – 7 lobed calyx which encloses 6 stamens. The pistillate flowers are solitary or on few to many flowered spikes which form in the axial of new leaves. Individual flowers consist of a 6 lobed calyx surrounding 3-celled ovary; the whole is partly covered by the involucre.
Fruits and seeds: The acorn is 1” long, usually paired, covered about 1/3 by its deep involucre; shining light brown nut, borne on a slender 1 – 4” long peduncle.