Quercus coccinea Münchh.

Scarlet oak is quite the starlet among North American oaks. Elwes & Henry (1906–1913) went as far as to say it is ‘the most ornamental species in North America’ – and it is not clear whether the contest extended beyond oaks. The key characteristic that sets Quercus coccinea apart is its vibrant, vermilion autumnal colour, but it is not the only one. Authors extol its rapid rate of growth, its attractive deeply lobed and many-bristled leaves, its lustrous green foliage in summer, and the well-developed crown, especially if it is given room to stretch its limbs. In addition, it tolerates a wide range of soils, both in terms of structure and pH, so long as they are well drained (it prefers acid soils, but does not suffer chlorosis in alkaline soils to the degree that the closely related Q. palustris does). Where it comes up short is in timber quality, being fit only for making casks for dry goods, according to Loudon (1838); it is used, however, for cabinetry, flooring, and veneer (Meier 2008).

It has a wide distribution in the eastern United States, found in every state east of the Mississippi save Florida, and also in pockets in Missouri and Arkansas; it has developed best in the Ohio River Basin (Johnson 1990). It grows mainly on drier upland soils, on ridges and mountain tops up to 1500 m. At high elevation, it can form a krummholz (wind-sheared) thicket, as on Rabun Bald, Georgia’s second-highest peak (1431 m) (Dirr & Warren 2019​​​​​​). It is the dominant oak in the Piedmont plateau and the Appalachian mountains, and it is rarer further north in its range. According to Miller and Lamb (1985), in the wild it starts bearing fruit age twenty and produces good to average crops every three to five years.

The foliar fireworks that inspired both its common and scientific names usually begin later than other oaks, but persist for around six to eight weeks. Be warned, however, that autumn colour is said to be variable and inconsistent from tree to tree, and early frost may cause the leaves to wither before colouring properly. According to Bean (1976), trees raised from seed cannot be relied on always to produce the sought-after autumnal hues; Dirr and Warren (2019), on the other hand, note that fall colour can be reliable on seed-grown trees, if the seed source is good.

Another feature that sets it apart from other oaks is the dappled shade it casts, making it an ideal shade tree for larger spaces. It is even possible to garden beneath it, as enough sunlight filters through the canopy to sustain shade-loving shrubs (White House Natives 2023).

Its wide-spreading crown makes Quercus coccinea unsuitable for street planting, unless there is sufficient space, such as on Massachusetts Avenue in Washington DC, which is lined with it; it is well suited for urban lawns and parks, as attested by a fine specimen in Central Park, New York (pers. obs. 2022, see photos below) and the avenue of scarlet oaks planted in Brooklyn Botanic Garden, New York, known as the Liberty Oaks, originally replacing Acer platanoides planted in 1918 to mark Armistice Day and the end of World War I, and later dedicated to the memory of the September 11 attacks and their victims (Cameron 2022). It is the state tree of the District of Columbia. A particularly fine tree grew at the northeast corner of the White House Grounds by Pennsylvania Avenue, planted by President Benjamin Harrison in 1892, but was felled in October 2007, having already lost a large limb in 1987 (a replacement scarlet oak planted by President George W. Bush in 2008 failed and the spot was chosen by President Barack Obama for a Tilia cordata) (Sternberg 1992; National Park Service 2023).

Quercus coccinea can easily be confused with other red oaks, in particular Q. palustris and Q. rubra. Features to look for are the C-shaped sinuses (as a mnemonic aid, recall the three Cs in the epithet), the buds covered in reddish hairs only in the top half, and acorns as wide as long and with concentric grooves around the tip (Dirr & Warren 2019).

The species was one of the earlier exotics to reach Europe, arriving in England before 1691, at which date it was listed as growing in the garden of Bishop Compton, probably sent to him by John Banister (Loudon 1838). It is widely planted in UK and European collections. A huge 19 m × 124 cm dbh tree grew at Brooklands Community Park in Weybridge, Surrey, UK, till it fell in 2013, ceding the girth champion title to a tree in Longstock Park and Water Gardens, Hampshire, planted in 1948 and reaching 24 m × 123 cm in 2023. Many trees in UK gardens have grown taller than that: the crown for current champion rests on the 29 m tall head of a tree in Winkworth Arboretum, Surrey, and runners-up close on its tail include trees at Nymans, West Sussex (planted 1902, 28.4 m × 99 cm in 2023) and Borden Wood House, West Sussex (28 m × 95 cm in 2018) (Tree Register 2026).

Bigger specimens are recorded in Europe. A massive tree can be found in the Giardini della Villa Reale in Monza, Lombardy, glorying under the quasi-operatic moniker “La Quercia scarlatta”. It is said to have been planted by Eugène de Beauharnais, Napoleon’s adoptive son and Viceroy of Italy from 1805 to 1815. The tree was presumably planted while he was Viceroy and has thus lived over two centuries, reaching a staggering 2.1 m dbh (i.e. wider than it has been found in its native range). The tallest specimen recorded in Europe is at L’Arboretum de Payssas, Lasseube, Pyrénées-Atlantiques, France, planted in 1930 and reaching 34.5 m in 2021 (monumentaltrees.com 2023).

By comparison, the US national champion tree, growing in Mercer Co., New Jersey, is taller at 39 m but at 1.62 m dbh thinner than the European giants (American Forests 2023). The species is widely cultivated in North American gardens and parks.

At Eastwoodhill, the National Arboretum of New Zealand, trees planted by founder Douglas Cook are the principal providers of the autumn colour for which the arboretum is famous. Seed from this species has been distributed widely via local nurseries, prompting former curator Garry Clapperton to fantasize that in the future “the autumn face of New Zealand … is going to be a brighter and deeper red” (Cameron 2014). It also colours up nicely at San Miguel Arboretum in Argentina (pers. obs. 2016).

Frist described by Münchhausen in 1770, the epithet, presumably based on the pre-existing common name “scarlet oak” (scharlach Eiche in the original publication), means “coloured or dyed scarlet” and derives ultimately from a name for the insect that produces a gall found on Q. coccifera (q.v.). The insect was crushed to prepare a bright red dye.