Kindly sponsored by
William & Griselda Kerr
Tom Christian (2021)
Christian, T. (2021), 'Eucryphia' from the website Trees and Shrubs Online (treesandshrubsonline.
Columnar trees or shrubs with glabrous or pubescent branchlets and sticky, resinous terminal buds. Leaves opposite, simple or pinnate, somewhat leathery, evergreen (except in E. glutinosa which is always deciduous, and some hybrids of E. glutinosa may only be semi-evergreen). Stipules are always present and caducous. Hermaphrodite, 4-merous flowers are produced singly or in small clusters forming an open bowl of white petals. Calyx lobes imbricate, united at their apices; detaching at floral maturity by abscising at the base, forming a four-lobed calyptra. Fruit a woody capsule with distinctive persistent styles. (Bausch 1938; Dress 1956; Wright 1983; Harden 2000).
There are seven species of Eucryphia, three in mainland Australia, two in Tasmania and two in southern South America (Forster & Hyland 1997). This classic Gondwanan distribution is indicitive of the evolutionary origins of the genus and of the family it belongs to, the Cunoniaceae, predominantly distributed in high-rainfall areas of the tropical and temperate southern hemisphere, especially Australasia. Within our study area of the northern temperate regions, Cunoniaceae is probably most familar to gardeners in the guise of Eucryphia, but the genera Caldcluvia and Weinmannia may also be familiar to growers in the mildest and wettest northern gardens (Grimshaw & Bayton 2009).
In those areas where they may be grown, Eucryphia are justifiably popular garden plants on account of their white flowers borne in late summer and, in all but one case, their evergreen foliage. The larger species are among the most attractive of flowering evergreen trees hardy in our area (Grimshaw & Bayton 2009). Most have been well known for some time but two were discovered relatively recently in Queensland, Australia. Eucryphia wilkiei was first found in 1970 and has been introduced to the nursery trade, but the 1994 discovery E. jinksii is not known to be in cultivation except in Australian botanical gardens and from a single plant kept in a conservatory in Northern Ireland (Paterson 2018).
The earliest recorded introduction to cultivation is that of E. lucida from Tasmania. Encountered by a French expedition that sailed to Oceania in 1791, it was introduced to Britain in 1820 and like so many Antipodean exotics it was initially treated as a tender plant for the conservatory. The Chilean species E. cordifolia and E. glutinosa followed in 1851 and 1859 respectively and by the early 20th century these three species were well established in European horticulture and some of the early hybrids were arising in cultivation. Both E. cordifolia and E. lucida received RHS Awards of Garden Merit in 1936, following the introduction to Britain of two further species – E. moorei in 1915 and E. milliganii in 1929 (Edwards & Marshall 2019). There is a record of the two Chilean species being introduced directly to the USA in early 1920 (USDA 1923) though it is not known whether this introduction properly established either in north American cultivation. Jacobson (1996) suggests E. glutinosa, E. × intermedia, and E. × nymansensis were all imported into North America, presumably from Europe, in c. 1937 and became commercialised there shortly afterward.
Following their introductions all the various species were found to perform well in mild oceanic gardens on acid soils along the western seaboard of Europe, but perhaps nowhere more so than in the gardens of Cornwall and Devon and across the island of Ireland: a useful description of Eucryphia growing in gardens in Northern Ireland, seen during an IDS Study Period in 2017, is given by Paterson (2018). Certain sheltered, inland gardens also proved suitable, such as Nymans in Sussex which has become inextricably associated with the genus. Several species and hybrids have proven remarkably hardy in colder UK gardens, especially those hybrids involving E. glutinosa which is probably the hardiest species, with high altitude provenances from Tasmania a close second. There is a record of E. lucida thriving on Isola Madre on Lake Maggiore, Italy in 1936 (Cocker 1936), but by the 2020s there are remarkably few examples of any species in gardens around the Italian lakes where the mild climate ought to be conducive to excellent growth (pers. obs. 2021).
The hardiness of E. glutinosa was to prove invaluable in expanding the cultivated range of the genus when this species was a parent to two hybrids – E. × nymansensis raised c. 1915, and E. × intermedia raised sometime before 1936. The various selections of these crosses, but especially their respective cultivars ‘Nymansay’ and ‘Rostrevor’, proved extremely adaptable and helped to popularise the genus through the rest of the 20th century; a sheltered plant of E. × intermedia ‘Rostrevor’ came through –18°C at Cluny House Gardens, Perthshire, in the 2010–11 winter (pers. obs. 2011). The first years of the 21st century, though, have seen an undeniable boom in the genus’s popularity at least within the UK and Ireland as species, hybrids and cultivars have all been profiled in the popular gardening press and advocated for their useful late-flowering and bee-friendly credentials. Very few are genuinely suited to small urban or suburban spaces, nevertheless they are becoming more frequently planted in such gardens. This has surely been helped by the relatively recent introduction of pink-flowered forms of E. lucida, and variegated forms of this and E. × nymansensis, all of which offer a fresh take on what was becoming a familiar aesthetic (Edwards & Marshall 2019). Their profile is similarly on the up wherever they will thrive – Europe’s Atlantic seaboard, the Pacific Northwest of North America, New Zealand, and increasingly in Australia as the greater use of natives is advocated.
In cultivation Eucryphia require moist but well drained acid soil, ideally with plenty of leafmould, in areas with at least moderate rainfall. Only E. cordifolia and to some extent E. × nymansensis are tolerant of lime and chalk soils. All perform best when the upper part of the plant is in full sun for at least part of the day, but equally they need their roots to be cool and shaded in order to really thrive, and plants benefit from appropriate companion planting to achieve this. Prolonged, cold winds can lead to severe scorching and shelter from the worst winter winds is advised (Edwards & Marshall 2019; Wright 1983). Propagation by seed is straightforward, but Eucryphia has a track-record of hybridising freely in cultivation and where several are grown together seed cannot be assumed to be true. Layering, and striking semi-ripe cuttings placed over gentle bottom heat, are usually reliable means of propagation. Cultivars must be vegetatively propagated.
This account of the eucryphias upholds a long-standing tradition in this genus of referring garden hybrids to nothospecies, however as their popularity broadens the most familiar selections are increasingly referred to as standalone cultivars. For ease of reference, a tabular list of the most popular cultivars is given below, with links to their respective parents:
|‘Castlewellan’||E. × nymansensis (cordifolia × glutinosa)|
|‘Daisy Hill’||E. glutinosa Plena Group|
|‘George Graham’||E. × nymansensis (cordifolia × glutinosa)|
|‘Gilt Edge’||E. lucida|
|‘Grayswood’||E. × intermedia (glutinosa × lucida)|
|‘Leatherwood Cream’||E. lucida or E. × hybrida (lucida × milliganii)|
|‘Madron’||E. × splendens (cordifolia × moorei)|
|‘Mount Usher’||E. × nymansensis (cordifolia × glutinosa)|
|‘Nymans Silver’||E. × nymansensis (cordifolia × glutinosa)|
|‘Nymansay’||E. × nymansensis (cordifolia × glutinosa)|
|‘Penwith’||E. × penwithensis (cordifolia × lucida)|
|‘Pink Cloud’||E. lucida|
|‘Rostrevor’||E. × intermedia (glutinosa × lucida)|
|‘Spring Glow’||E. lucida|
|‘Winton’||E. × hillieri (lucida × moorei)|
|1a||Leaf margins distinctly toothed||2|
|1b||Leaf margins entire, or weakly toothed in the upper half only||4|
|2a||Leaves simple, with distant, shallow teeth (teeth often much reduced on flowering shoots)||Eucryphia cordifolia|
|3a||Leaves mostly trifoliate-compound with only one pair of lateral leaflets subtending the terminal leaflet; leaflets crowded, sometimes overlapping; plants evergreen||Eucryphia × nymansensis|
|3b||Leaves mostly with 2 pairs of lateral leaflets; leaflets well-spaced on the rachis, usually not overlapping; plants deciduous||Eucryphia glutinosa|
|4a||Leaves mostly simple||5|
|4b||Leaves mostly compound||8|
|5a||Leaves mostly <2 cm long||6|
|5b||Leaves mostly >3 cm long||7|
|6a||Leaves mostly <1.4 × 0.6 cm||Eucryphia milliganii|
|6b||Leaves mostly >1.5 × 0.8 cm||Eucryphia × hybrida|
|7a||Leaves at least 3 × longer than broad, usually <1.5 cm broad, margins more or less flat||Eucryphia lucida|
|7b||Leaves less than 3 × longer than broad, up to 3 cm broad, margins obviously wavy||Eucryphia × penwithensis|
|8b||Leaves green, grey-green, or creamy beneath||9|
|8a||Leaves glaucous or glaucous-grey beneath||10|
|9a||Leaves green or grey-green beneath||Eucryphia × intermedia|
|9b||Leaves cream or creamy-grey beneath||Eucryphia jinksii|
|10a||Leaves with lateral leaflets of more or less equal size||11|
|10b||Leaves with basal pair of leaflets always the shortest; leaflet length clearly increasing up the rachis toward the terminal leaflet||12|
|11a||Leaflet apices mostly acute-apiculate||Eucryphia wilkei|
|11b||Leaflet apices mostly short-mucronate||Eucryphia × hillieri|
|12a||Leaflets thick, leathery, broad; terminal leaflet to 12 × 3.5 cm||Eucryphia x splendens|
|12b||Leaflets thin, not leathery, narrow; terminal leaflet to 7 × 1.5 cm||Eucryphia moorei|