Quercus coccinea aka Scarlet Oak

Scarlet oak, Quercus coccinea, is a large deciduous tree in the beech family, Fagaceae. It is native to north-central and eastern North America. Its range runs from Maine south to the Southeast and west to Minnesota and Missouri. In the wild it grows in dry upland forests. The species name means scarlet and refers to its autumn colour.

In gardens the tree usually reaches 50 to 75 feet (15 to 23 m) tall. Some sources give up to 80 feet (24 m). It spreads 45 to 60 feet (14 to 18 m). Young trees are loosely pyramidal. With age they form a rounded, open crown on upright, spreading branches. For an oak it grows fast. It can take more than 50 years to reach full size.

Young bark is gray-brown with smooth streaks. Older bark turns dark and forms broad ridges and narrow furrows, with reddish inner bark. Stout reddish-brown twigs carry plump, pointed buds. The alternate leaves are 3 to 7 inches (8 to 18 cm) long and glossy dark green, paler below. Each has seven to nine bristle-tipped lobes separated by deep, C-shaped sinuses. That sinus shape helps separate it from pin oak, which has U-shaped sinuses. Autumn colour arrives late and ranges from russet to brilliant scarlet. Some trees hold dead leaves into spring.

Flowers appear in April and May as the leaves open. Male flowers hang in slender yellowish-green catkins, and female flowers form short spikes. Neither is showy. The acorns are 1/2 to 1 inch (1.3 to 2.5 cm) long. A deep, bowl-shaped cap covers about half of each nut. Acorns take two seasons to ripen, and trees start bearing at about 20 years old.

Scarlet oak needs full sun and well-drained soil. It does best in dry, acidic, sandy ground but accepts clay or loam if drainage is good. Once settled it tolerates drought and black walnut. It is hardy in USDA zones 4 to 9 and rated H6 in the UK. A deep taproot makes it hard to transplant, and nurseries rarely stock it. It suffers less chlorosis than pin oak in alkaline soils. It serves well as a shade, lawn or street tree, given enough room. Many moth and butterfly caterpillars feed on it, including the imperial moth and several hairstreaks. Birds and mammals eat the acorns. The strong, heavy wood goes into floors and furniture.

Serious problems are rare. Reported diseases include leaf spots, anthracnose, canker, mildew, rust, rots and honey fungus. It is highly susceptible to oak wilt. Thin bark leaves it open to fire damage. Pests include aphids, caterpillars, leaf miners and gall wasps. The leaves and acorns contain tannins and can harm people, dogs and horses. Even so, people can eat the acorns after leaching or boiling out the bitter tannins. Native Americans ground them for flour and roasted them as a coffee substitute.