Scarlet Oak is a large deciduous tree, not native to Minnesota, but grows well here, reaching from 60 to 80 feet high. It has a rounded to irregular open crown with many dead branches and a lower trunk without the stubs of old branches.
The bark is dark gray to gray-brown on young stems, with smooth streaks, becoming blackish, thick, and furrowed into scaly ridges and plates, especially near the base of the tree. The inner bark is an orangish-pink.
Twigs are reddish-brown with light colored lenticels. Buds are reddish-brown also, plump, pointed and with light brown hair in the upper half. The twig has multiple terminal buds that are 5-angled in cross-section.
Leaves are alternate, elliptical to oval in outline, deeply divided, nearly to the mid-vein or at least half way, with 7 to 9 lobes, each lobe ending in bristle tipped teeth (awns) that number 18 to 50. The sinuses between the lobes are wide and round forming more than a half circle. Stalks are long and slender. Secondary veins of the leaf appear raised on both surfaces. The upper surface is a shiny green, the underside pale green with tufts of hair along the mid-veins. The leaf tip is pointed, the base is blunt (truncate) to slightly pointed (obtuse). Fall color is scarlet.
Flowers: The tree is monoecious, that is with separate male and female flowers. Male flowers occur in slender yellow-green 2 to 4 inch hanging catkins from the leaf axils of last year's growth. Female flowers are on short stub spikes, containing 1 to several flowers, emerging from the leaf axils on new growth. They are reddish-green. Both appear with the leaves.
Seed: Acorn maturation is biennial, maturing to an egg-shaped acorn, 1/2 to 1 inch long, enclosed in a deep top-shaped cap with tightly pressed hairless scales that have concave margins, the cup tapering to a stalked base. (Oak acorns are highly variable as to cap coverage and acorn size by geographic location) The nut is reddish-brown when mature and usually has one or more rings of fine pits at the apex. The acorn matures in the second summer as do most species in the Quercus Sect. Lobatae - the Red Oak Group.
Habitat: Scarlet Oak grows from a deep taproot and spreading lateral roots. It preferred sites are dry upland slopes and ridges and is usually found in well-drained but generally poor soils. Full sun is required for a good shape. Scarlet Oak will hybridize with Northern Red Oak and Black Oak. Oaks should be pruned during the winter months, from October to March, to avoid open wounds where the Oak Wilt fungus can enter.
Names: The genus name, Quercus, is the Latin word for Oak. The species, coccinea, is from the Latin coccineus, for 'scarlet'. The author name for the plant classification - ‘Münchh’ is for Otto von Münchhausen (1716-1774) German botanist, correspondent of Linnaeus. He described several species of oak.
Comparisons: Scarlet Oak will look similar to Black Oak, Q. velutina, but the acorns of Black Oak have loose hairy scales, especially at the fringe of the cup. Both have tufts of brown hair on the leaf underside at vein junctions. The leaves of Scarlet Oak are similar to Pin Oak, Quercus palustris, and Northern Pin Oak, Q. ellipsoidalis, and if you find a similar leaf in Minnesota in the wild it will probably be Northern Pin Oak. Another similar oak to compare is Northern Red Oak. Check the Oak Leaf Comparison Sheet.
Below: 1st photo - The male flowers occur in hanging catkins from buds at the end of the prior year's twigs. 2nd photo - Twigs are reddish-brown with light colored lenticels. Buds are plump, pointed and with light brown hair in the upper half. 3rd photo - Bark becomes blackish, thick, and furrowed into scaly ridges and plates, especially near the base of the tree.
Below: 1st photo - Female flowers form on short spurs from the leaf axils on new growth. 2nd photo - Mature Acorns - photo ©Steven Hurst, USDA-NRCS Plants Database.
BELOW: 1ST photo - This developing acorn is on a stalk, long for an acorn. 2ND photo - The upper surface of the leaf is glossy green.
Below: Leaves can be variable in shape, elliptical overall, with some lobes divided almost to the mid-rib. The only hair is in the vein intersections on the leaf underside (3rd photo).
Below: The fall color of Scarlet Oak usually does not disappoint.
Notes: Scarlet Oak is sometimes noted to be indigenous to the Wildflower Garden but as the nearest known native populations are in southern Illinois and southern Missouri and eastward from there into the Appalachians, it is not indigenous but if present in the early years of the garden it was undoubtedly planted from nursery stock. Gardener Cary George reported planting the tree in 1994 but it is not listed on the latest Garden census.
There are six species of Oak generally found in parts of Minnesota that are not considered hybrids or rarities that have not been collected in the last 100 years. These are: White Oak, Q. alba; Swamp White Oak, Q. bicolor; Northern Pin Oak, Q. ellipsoidalis; Bur Oak, Q. macrocarpa; Northern Red Oak, Q. rubra. and Black Oak, Q. velutina. Chinkapin Oak (Chestnut Oak, or Yellow Oak), Q. muhlenbergii was native but is historical only now, last collected in 1899; Scarlet Oak, Quercus coccinea, can also grow here as can Pin Oak, Quercus palustris, but neither are native.
Wood & its Uses: Scarlet Oak is used for its lumber which is usually marketed as Red Oak which is used for flooring, cabinetry, furniture, millwork and many rougher uses and except for certain specialized uses such as liquor barrels, it has replaced White Oak due to its rapid growth characteristics. It is heavy, hard, strong, coarse-grained and machines well.
It is difficult visually to separate the species of the Red Oak group when you are looking a piece of lumber. As a general characteristic the Red Oak group has wood with the tallest rays less than 1 inch and the latewood pores are few and distinct. Whereas, in the White Oaks the tallest of the largest rays are greater than 1-1/4 inches and the latewood has numerous small pores that grade into invisibilty. A small hand lens is necessary to do this.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"