Quercus falcata Michx.

Quercus falcata is an oak that grows where others won’t. According to Sternberg (2004) it can subsist on some of the most abused, degraded red soils of the southeastern US, while Dirr and Warren (2019) recommend it as an option for ‘where soil conditions are miserable.’ Growing in poor conditions takes its toll, and old specimens in natural habitat often look weather-beaten and unkempt due to their struggle to overcome hardship, but in a favorable location it can make a remarkable tree and where the soil is good exhibits rapid growth (Sternberg 2004). As Warren and Dirr put it, it is a species ‘with the genes to achieve nobility’; they extol its tremendous soil adaptability, including clay. It is recommended for use in restoration of impoverished soils and wildlife habitats. The only caveat is that it is sensitive to root disturbance during construction, which can prove lethal (Dirr & Warren 2019).

It is one of the common upland species of the US Southeast, and its range extends as far north as Long Island and New Jersey. In the north, it forms a small tree about 10 m high, and the leaves tend to be three-lobed and not falcate, save for some in the upper section of the canopy. These differences led A. Michaux to describe the northern form as a different species, Quercus triloba. For some authors, this constituted a var. of Q. falcata, but it is now considered a synonym (Michaux 1801).

Its attractively elongated and variable foliage, with curved, svelte lobes one might fancy had been drawn by Parmigiannino, is enhanced by the tawny pubescence that highlights the undersides. Despite these assets, it has not been taken up widely in cultivation, and no cultivars have been introduced in the nursery trade, probably due to its prosaic autumn colour.

Quercus falcata was introduced to the UK early on, in 1763, as Q. elongata (see below), but presumably did not take hold, as a reintroduction is reported in 1800, as Q. triloba (Loudon 1838). Elwes and Henry (1906–1913) wrote that it was ‘extremely rare in cultivation’ and only knew of two mature trees at Kew, about 8 m high. These have evidently since succumbed, but Kew holds the current UK and Ireland champions: a tree planted in 1928 tops the ranking for girth, with a dbh of 94 cm, while another planted in 1930 reached 24 m (both measured in 2022), making it champion for height, a title it shares with a tree growing in Warnham Court, West Sussex, of unknown age (The Tree Register 2024). A hybrid with Q. velutina grows at the Morris Arboretum, Pennsylvania, USA. It derives from seed collected at the Mt.Cuba Center, Delaware.

This species was described in 1801 by Michaux. His publication was neck and neck with Willdenow’s publication of Q. elongata for the same taxon, in a footnote in an article by Mühlenberg, which was published later in the same year (Mühlenberg 1801). Then the species had a rough nomenclatural time of it in the late 19th and early 20th centuries. Sargent in 1889 claimed that Michaux had been beaten to the post by earlier authors who had described this species, singling out Wagenheim’s Q. cuneata as the first (published in 1787, it is now considered a synonym of Q. marilandica). Elwes and Henry (1906–1913) followed Sargent’s lead, listing the species as Q. cuneata. Sudworth (1892) thought that Marshall’s name Q. nigra var. digitata (1785) had precedence, and coined Q. digitata, which was adopted as the correct name by Sargent in 1895 and Trelease in 1912. The epithet refers, according to Marshal, to the ‘somewhat finger-shaped lobes,’ and to this day the resemblance of the elongated central lobe to a middle finger is used for identification (W. Daniel, pers. comm. 2024). By 1905, Sargent had decided that Linnaeus had been the first across the line in 1753, because he understood the species to be what Linnaeus meant by Q. rubra (Trelease agreed with him in 1924). Indeed, Castiglioni (1790) had placed the taxon in Q. rubra as a variety he called hispanica, presumably based on the common name in the US (Spanish Oak). By 1935, however, Q. falcata seems to have been safely restored, for example, in Palmer & Steyermark (1935).

André Michaux chose the epithet falcata (= sickle-shaped, from Latin falx = sickle or scythe), in reference to the shape of the lobes (‘lobis subfalcatis’ in his description, i.e., sort-of-like a sickle). The common name ‘Southern Red Oak’ is straightforward, but the origin of ‘Spanish Oak’ is opaque. The use of the name dates back to the 17th century (e.g. Penn 1683). François-André Michaux (son of André) wrote that in a library in Charleston he found an ‘old English work’ in which ‘it is said to have been called Spanish Oak by the first settlers, from the resemblance of its leaves to those of the Quercus velani which grows in Spain’ (Michaux 1842). This is doubly problematic: Q. velani presumably refers to the Valonia Oak, Q. macrolepis, which does not grow in Spain and has only a passing similarity to Q. falcata. And would the first settlers have been familiar with Q. macrolepis? Elwes and Henry doubled down on Michaux’s proposition, claiming that the name is due to a resemblance to Q. cerris, a hypothesis that falls short on the same two counts. Other theories suggest a resemblance of the lobes to a Spanish dagger, or that its autumn colour combines the colours of the Spanish flag, red and yellow (it doesn’t: it is usually a dull reddish brown) (Missouri Department of Education 2024). Some say it was called Spanish Oak because its native range includes former Spanish colonies (Lady Bird Johnson Wildflower Center 2024). But former Spanish territories did not extend much further north than Florida on the East Coast of the US, and the range of Q. falcata does not extend south beyond northern Florida. And plenty of other oaks are found in that region. ‘Spanish’ is also applied to Q. palustris, known to some as ‘Spanish Swamp Oak’, the derivation of which also defies explanation.