Quercus rysophylla Weath.

Quercus rysophylla is very much a stand-alone oak, both taxonomically (though relatively widespread, it is so distinctive as to have no synonyms or infraspecific taxa) and horticulturally (no other oak has been singled out so often as the oak to have, should you have to choose only one species). Writing in New Trees (Grimshaw & Bayton 2009), John Grimshaw wrote: ‘Of all the trees in this book, Quercus rysophylla is the one that has made the greatest impression on me, wherever it has been seen, and if only one ‘new tree’ were to be grown, this should perhaps be it.’ This echoes earlier comments by American horticulturist John Fairey who has been quoted as saying ‘If I had to have one oak, it would be rysophylla’ (Raver 2012). As the first cultivated trees reach their full potential, so the species is becoming increasingly well known and widely planted.

The species is endemic to Mexico’s Sierra Madre Oriental. Its largest populations occur in the states of Nuevo León and Tamaulipas, extending south into the Sierra Gorda, where it is found in the more humid parts of Querétaro, San Luis Potosí and Hidalgo. Muller (1936) described it as common on densely wooded canyon floors and up to 25 m tall in two municipios of Nuevo León (Villa Santiago and Potrero Redondo). The wood of Q. rysophylla is heavy and is used locally for various construction purposes (Cruz de León 1994).

Although this has become a very desirable tree, it was a relative latecomer to cultivation compared to some other Mexican oaks. The first introduction was made by Lynn Lowrey, who probably first collected it in the 1970s. Lynn Lowrey (1917–1997) was a Texas horticulturist and plant collector who pioneered the use of native and rare plants in the landscape. He first visited Mexico in 1937, and he returned often to introduce new plants to cultivation. He collected Quercus rysophylla several times, and he almost certainly gave it the name Loquat Oak. Seed from his 1978 collection at Horsetail Falls, Nuevo León (known as Cascada Cola de Caballo in Mexico, a spectacular 25 m waterfall in the Parque Nacional Cumbres de Monterrey), made its way to the Hillier Nurseries and was the first introduction to Britain.

Sir Harold Hillier had many nurseryman friends in the southern USA, and in 1979 he was invited to join some of them, including Benny Simpson, Tom Dodd and Gene Cline, on a visit to Texas and Mexico (Hillier 2014). In Mexico he met Lynn Lowrey, who showed him the Horsetail Falls location where Q. rysophylla grows. Sir Harold made his own collections of Q. rysophylla there, and collected many other species in different parts of Mexico during his visit. It took a few years from these early introductions for the potential of Q. rysophylla to be appreciated, but as its beauty became apparent, it attracted the interest of oak enthusiasts. What must have been one of the first mentions of Q. rysophylla in the horticultural literature was its inclusion in thesixth edition of The Hillier Manual of Trees and Shrubs (Hillier Nurseries 1991), the description made from a tree then 5 m tall at the Sir Harold Hillier Gardens, Hampshire, UK.

Further introductions were made by Allen Coombes, from seed collected at the Horsetail Falls in 1996, and in northern Hidalgo, close to the border with Queretaro, in 2008. Seed has been collected mainly from Nuevo León by others since then, including Bob Berry, Guy Sternberg, Thierry Lamant, Sean Hogan and Rubén Marroquín. Seed from cultivated plants has also been collected and distributed, and in many such cases this has resulted in hybrid progeny.

Quercus rysophylla seems to thrive almost everywhere it is grown, from western Europe to the southern and western USA, and elsewhere around the globe (e.g. New Zealand, Australia, Argentina), always growing best in areas with warm summers. Where it grows well, it can survive extremes of heat and cold, and a surprising amount of drought. No reports of disease or insect damage were received by Coombes (2016). However, Q. rysophylla is unlikely to survive extreme cold in central or northern Europe or the central USA, and areas with mild winters but cool summers, such as northern Britain, are also likely to be limiting. In such areas it is possible that hybrids with hardy red oaks could produce plants better suited to such conditions and with the ornamental characters of Q. rysophylla, such as the impressed veins and red young foliage.

Indeed, acorns collected from cultivated trees tend to produce hybrids, unless a grove of several trees is planted (as at Arboretum de la Bergerette, see below). Some hybrids, particularly ‘Maya’, have become quite well known in gardens – see Quercus rysophylla hybrids for further discussion. To obtain the true species, cuttings offer a viable alternative method. According to Sean Hogan (2008), this can be done with relative ease: most of his batches came through with 70–80 % rooting in only a month or two with bottom heat and mist. The recommended time to take cuttings is in November to January (northern hemisphere).

The tree at the Sir Harold Hillier Gardens is perhaps the best known in the UK and is from Hillier 622, collected at the Horsetail Falls in 1979 and planted in the early 1980s. It reached 19.6 m in 2017 and may still be the tallest in the country, though trees at Kew, measured five years later, have surpassed that mark: one, also from Hillier 622, was 20.5 m tall in 2022 and another, grown from seed donated by Lady Anne Palmer, derived from a collection by Bob Berry in Chipinque Park, Monterrey, in October 1991, was even taller at 21.3 m. Their dbh (51 cm and 53 cm, respectively) have not yet exceeded the 2017 mark of 58 cm attained by the Hillier tree, which is the UK and Ireland champion for girth (The Tree Register 2025), and probably still the champion for height as well. According to data reported by Coombes (2016), it grew 2 m in the seven years from 2008 to 2015, and at that rate would have reached 21.6 m in 2022. Hugh Angus (2014) mentioned that this tree has survived –18°C, which may have been a winter when it lost all its leaves. The tree, however, did not blink, and the following year looked as good as ever (pers. obs. AJC).

This species might be expected to do well in the south of England, but there are also plants further north and in colder parts of the country. A fine young tree is growing well in a sheltered position at Thenford House, Northamptonshire, in the collection of Lord Heseltine, and a little further north, it grows at Gredington, Shropshire, planted by the late Lloyd Kenyon. There are two trees, the larger of which, at 5 m tall in 2015, is probably a hybrid; the smaller one, grown from seed collected in Mexico in 2009, is true to name. In Wales, Thomas Methuen-Campbell grows Q. rysophylla at Penrice Castle. He has three plants from Allen Coombes’s 2008 collection in Hidalgo, which were about 1.5 m tall in 2015. A fine young tree at Roath Park, Cardiff, is described as the Glamorgan Champion (Cardiff Parks 2025). In May 2023, it was 14 m × 93 cm. The excellent photographs on the Cardiff Parks website show that this tree is correctly named. No trees of true Q. rysophylla are known in northern England or Scotland, but neither have we found evidence that it has been tried unsuccessfully there.

Creech (2016) wrote a glowing report on the fine tree of Quercus rysophylla growing at Stephen F. Austin State University, Nacogdoches, Texas. This tree, planted by Creech in 1988 from a collection by Lynn Lowrey, was over 18 m tall in 2011 and 51.7 cm dbh in 2016, and Creech considered it to be the largest in the USA. It survived a record low of –18°C in 1989, two hurricanes (Rita in 2005 and Ike in 2008), and record heat and drought in 2010 and 2011. In addition, Creech noted that it is not affected by tent moth caterpillars (Malacosoma americanum), which have caused problems with many of the native oaks there. Peter Loos (pers. comm. 2015) reported that he had seen the leaves of this tree turn black and the tree defoliate in one cold winter. According to Creech, about 90% of the seedlings from this tree come true. It is possible that the tree is pollinated by other specimens of the species growing there, although these are several hundred meters away. There are also three large trees at Trinity University, San Antonio, Texas that are suspected to be Lynn Lowrey collections; the largest was estimated to be around 25 m tall in 2023, possibly a contender for the title claimed by Creech for the Nacogdoches tree (Cameron 2024). These trees in Texas may be the largest in cultivation, as they surpass measurements of trees in Europe, and are likely to be older. The tree at Chocha, France (see below) may also be in the running.

A tree at the University of Washington Arboretum, Seattle, probably qualifies as the most northerly location where this species is planted in the US. Collected south of Monterrey, Nuevo León, it was received from Lynn Lowrey as a 45 cm seedling in 1983 and planted in its current position in 1992 (Coombes 2016).

The largest specimen in Europe is likely one at Chocha Arboretum in southwest France. It was obtained as a 50–60 cm plant from Mallet Court at Courson in 1992, and was 12 m tall in 2004 (Grimshaw & Bayton 2009) and by 2015 was c. 20–25 m and 57.3 cm dbh. This tree is the parent of Q. ‘Chocha’ (see Quercus rysophylla hybrids). An accurate measurement could prove it to be the largest example in cultivation. The 2015 dbh measurement is slightly larger than that of the tree at Hillier Gardens at that time. At Arboretum des Pouyouleix, France, there is a group of six trees planted in 2008 that are about 13 m tall and up to 40 cm dbh (Chassé 2025). The species can be found in several other European collections (for details, see Coombes 2016).

In the Southern Hemisphere, Quercus rysophylla is found in New Zealand (Hackfalls Arboretum and Eastwoodhill Arboretum), from seed collected by Bob Berry in Chipinque near Monterrey in 1990. One of these was 16.8 m × 52 cm in 2020 (Hackfalls Arboretum 2025). It also grows in Australia, at Bill Funk’s Mereweather Arboretum, from seed collected in Nuevo León. Two trees were around 5 m tall in 2015, and around 10 m tall in 2025 (B. Funk, pers. comm. 2015; pers. obs. RC 2025). A strongly upright tree grows in Perth at the Government House Gardens, about 15 m in 2025. A more sprawling specimen is found in the Tasmanian Arboretum, about 10 m in height. The origin of these trees is unknown, but they may have been sourced from Bill Funk (B. & K. Cerlienco, pers. comms. 2025), as was a finely structured, pyramidal tree, some 12 m tall at Geoff Bogle’s arboretum near Hoddle’s Creek, Victoria. In Argentina, a specimen planted in 2001 thrives at Grigadale Aboretum, despite a close shave in 2011 when it severely declined, likely due to waterlogging, and as a premature swan song turned a striking crimson in autumn. A hard pruning in 2013 produced strong leaders, one of which was removed in 2015, and it has since recovered, reaching an estimated 15 m × 38 cm in 2025, but never repeating the autumnal show of 2013 (Cameron 2014).

Although several cultivars have been attributed to Quercus rysophylla, all these have been found to be of hybrid origin, and there are no cultivars of pure Q. rysophylla. Several hybrid cultivars have been named and are found in collections and offered in nurseries. For more details, see Quercus rysophylla hybrids.

Quercus rysophylla is known in the USA as Loquat Oak or Loquat-leaf Oak, from the superficial resemblance of the leaves in shape and texture to those of the loquat (Eriobotrya japonica). In Santiago, Nuevo León, it is called encino de asta (Marroquín 1997), which translates as flagpole oak, presumably referring to its fast growth and the straight trunks of young trees. The name encino de asta has also been applied to another Mexican red oak, Q. calophylla.

This epithet derives from the Greek ῥυσός (rhysos) meaning ‘shrivelled, wrinkled’ and φύλλον (phyllon), leaf. Epithets derived from ῥυσός (rhysos) are not common. Aside from Weatherby’s name, few published epithets have this derivation (e.g. rysopodum, rhysocarpa, ryssosperma), as well as a handful of generic names (Rhysolepis, Rhysosermum, Rhyssopteris, etc.). Weatherby was the first author to publish an epithet derived from ῥυσός, and Q. rysophylla is the only instance of the epithet. This would confirm his familiarity with the classics. The word ῥυσός is used, for example, in The Iliad, to describe prayers, personified as daughters of Zeus: ‘one may imagine them lame, wrinkled things with eyes cast down, that toil to follow after passionate Folly’ (Book 9, ll. 502–504, Fitzgerald 1974).