The Oaks of the genus Quercus account for more tree biomass than any other species in North America and Mexico (1). Scarlet Oak is a large deciduous tree, not native to Minnesota, but grows well here in certain conditions, usually 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 largest known Scarlet Oak in the country is in Mercer NJ (2012) measuring 128 feet high, 112 foot crown spread, 201 inches in circumference and scoring 360 points.
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 are a yellow-green, appearing in slender catkins, 2 to 4 inches long at the ends of the prior years growth. Each male flower has six stamens (can very from 2 to 12), which have long spreading white filaments when the flower fully opens. The female flowers are more reddish-green and appear as small slender spikes in the axils of new growth. They have 3 (to 6) carpels and styles that are slender and short. There are no petals; both sexes have the sepals are fused together. Both appear with the leaves.
Seed: Acorn maturation is biennial; they are oblong to subglobose in shape, maturing to be 1/2 to 1 inch long, enclosed 1/3 to 1/2 in a turbinate to hemispheric cap, scales with broad glossy base, scale margins often strongly concave (tightly appressed); nut ovoid to subglobose, with 1 or more concentric rings of pits at apex. (Oak acorns are highly variable as to cap coverage and acorn size by geographic location) The nut is reddish-brown when mature. Caps do not expand as the acorn grows longer. 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 Fall color of the leaves and the wood is also reddish. The author name for the plant classification from 1770 - ‘Münchh’ is for Otto von Münchhausen (1716-1774) German botanist, correspondent of Linnaeus. He described several species of oak. However, the common name was applied by Andre Michaux - see notes below.
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 which is the most closely associated oak speces. The acorn of Northern Pin is 1/2 to 1 inch long, 1/3 to 1/2 enclosed in a deep cup to top-shaped cap with tightly pressed scales which are finely hairy and have straight or slightly concave margins. The cap tapers abruptly to a stalked base. Another similar oak to compare is Northern Red Oak. Check the Oak Leaf Comparison Sheet.
Above: A Scarlet Oak just beginning to show Fall color. Drawing from Michaux, Francois – The North American Sylva or A Description of the Forest Trees of the United States, Canada and Nova Scotia Vol. I
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. The cup does not increase in size as the maturing acorn grows. 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.
(1) Ascent of the Oaks, Hipp, Manos, Cavender-Bares, SA, Aug 2020.
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 cannot be indigenous. The U of M Herbarium states on their Checklist (Ref. #28C) that the indigenous idea was based on a mis-identified specimen. In 1926 Eloise Butler wrote of the trees in her Native Plant Reserve and stated that there was one tree only of Q. coccinea in the Garden, but her garden log contains no note of previously planting it. However, she did introduce the tree on Oct. 6, 1928 when she brought in a tree from Kelsey’s Nursery in Salem MA. 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. However, it did not have the desired characteristics to please Francois Michaux.
Here is what he wrote in North American Sylva - 1817-1819 (Ref. #26b): "The name of Scarlet Oak was given by my father, and through not in use by the inhabitants, it will probably be adopted. At this season [Autumn] the singular colour of the foliage forms a striking contrast with that of the surrounding trees, and is alone a sufficient inducement to cultivate the tree for ornament.
The wood of this Oak is reddish and coarse-grained with open pores. As it decays much more rapidly than the White Oak, it is employed by the builder and wheel-wright only from necessity or economy. It is poor fuel and is used principally for staves. That this tree will flourish in France, is shown by an example at Rambouillet, where it makes part of a beautiful plantation 45 feet in height, formed in 1786, of species sent home by my father soon after his arrival in the United States. It is to be regretted that so fine a tree, which is so well adapted to our soil, should afford such indifferent wood that we cannot recommend it introduction into the forests of Europe, nor its preservation in those of the United States."
Francois Michaux's father was Andre Michaux - (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. Two important works were the Histoire des chênes de l'Amérique septentrionale (1801 - Oaks of North America), and the Flora Boreali-Americana (2 vols., 1803). His son Francois, traveled with him and the father’s notes were later used for the 3-volume North American Sylva, for which Thomas Nuttall provided some supplements.
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 invisibility. 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.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"