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An evergreen or semi-evergreen tree to 20 m tall, intermediate between its parents E. glutinosa and E. lucida. Young shoots slightly grooved. Leaves occasionally simple, especially on flowering shoots, but usually trifoliate-compound with one large terminal leaflet and two much smaller laterals, borne opposite. Simple leaves and terminal leaflets to 6 cm long with a short petiole. Lateral leaflets smaller, to 3 cm long, more or less sessile. Margins of simple and compound leaves entire, shallowly wavy, sometimes shallowly toothed toward the apex, flowers borne singly or in pairs at branch apices, 2–3(– 4) cm across, petals pure white, widely obovate and overlapping (Bausch 1938; Cullen et al. 2011).
USDA Hardiness Zone 8a-11
RHS Hardiness Rating H5
This hybrid between the deciduous Chilean E. glutinosa and the evergreen Australian E. lucida arose in cultivation during the early 20th century. It was first spotted in the garden of Sir John Ross-of-Bladensburg at Rostrevor in County Down, Northern Ireland. (Bean 1981). Seedlings intermediate between the two parents were first noticed by Sir John’s head gardener, John Rodgers (S. O’Brien pers. comm. 2018). We may assume that these and subsequent hybrid seedlings were removed and carefully tended before their inevitable distribution among Sir John’s friends, including to Lord Aberconway at Bodnant. It was Lord Aberconway who first exhibited this cross, under the name ‘Rostrevor’, at the RHS show at Vincent Square on 1st September 1936, where ‘Rostrevor’ receivd an Award of Merit (Bean 1981).
It stands to reason that this spontaneous hybrid would have occurred in numerous gardens at different times, with the result that E. × intermedia is actually a more variable entity than is generally considered. Furthermore, back crosses are known at least with E. lucida (see ‘Grayswood’ below) which further diversifies the variation that must be accepted under the name E. × intermedia. Unfortunately, because ‘Rostrevor’ is generally considered to be the principal representative of the hybrid in gardens, this name appears to have been too-freely applied to selections of E. × intermedia with the result that plants labelled ‘Rostrevor’ exhibit cosiderable variation in leaf size and shape, in flower size, and in the timing of flowering (pers. obs.).
This obscure cultivar was purportedly raised at the garden at Grayswood Hill, Surrey, England, where the original tree was 11 m tall in the late 1990s. Another at the Sir Harold Hillier Gardens had, by 2001, achieved nearly 6 m height in 21 years since planting. There is also a multi-stemmed tree of c. 7 m height at High Beeches garden in West Sussex, England, where the accession cards attest to this particular individual’s pedigree – it was a gift direct from Grayswood Hill in 1969. The High Beeches accession card also reveals that ‘Grayswood’, while undeniably similar to ‘Rostrevor’, is subtly different. The parentage is given as ‘(E. glutinosa × E. lucida) × E. lucida’, and this is backed up by a verification made by Christopher Brickell dated 1980 (pers. obs.).
In spite of this pedigree, it is not surprising that there is little in the gross morphology of ‘Grayswood’ to make an immediate and striking distinction from ‘Rostrevor’, except perhaps that the occurrence of simple leaves (a character of the E. lucida parent) is more frequent in the High Beeches plant of ‘Grayswood’ than in specimens of ‘Rostrevor’ (pers. obs.). Sarah Bray (pers. comm. 2018) says that it ‘flowers magnificently’ each year, but even so it is likely to only be of interest to the most avid collectors of Eucryphia. In 2015, Plant Heritage listed it as ‘vulnerable in cultivation’ (Plant Heritage 2015) and it does not appear to be commercially available anywhere, nor in cultivation outside the south of England.
The name ‘Rostrevor’ is the clonal name for the original cross of E. lucida and E. glutinosa, which was extensively propagated and distributed (Bean 1981). As discussed in the main E. × intermedia article above, however, it is likely that other occurences of this cross, both spontaneous and deilberate, soon followed, and unfortunately the name ‘Rostrevor’ has probably been erroneously assigned to many of these later entities with the result that today plants labelled ‘Rostrevor’ can be very variable.
The genuine, original ‘Rostrevor’ quickly became established in the nursery trade first in the UK and Ireland, and then in North America by the end of the 1930s (Jacobson 1996). Its hardiness is generally considered to be on a par with E. × nymansensis and there are fine examples growing in relatively cold locations, for example an 11 m tree at Drummond Castle, Perthshire, and a 12 m tree at Keir House, Dunblane, both in Scotland. The milder west coast of Scotland in naturally home to larger examples, indeed the largest known grows at Glenarn, near Helensburgh on the Firth of Clyde and in 2012 was 20 m tall. There are many examples in excess of 10 m height throughout the UK and Ireland, concentrated in milder western regions and across the south of England (The Tree Register 2018).
It is grown on the west coast of North America, for example at Washington Park Arboretum (University of Washington Botanic Gardens 2018) and at Heronswood, Washington State, USA. Heronswood nursery supplied a plant to the JC Raulston Arboretum in North Carolina in 1996, but this is not recorded as having survived in 2018 (JC Raulston Arboretum 2018). It is cultivated in New Zealand, for example at the Eastwoodhill Arboretum (MacKay 1996) and probably in Australia, although there is very little information available from here. It is commercially available from numerous European nurseries in the UK, Ireland, France, the Netherlands and Hungary.
Bean (Bean 1981) asserts that this is a ‘vigorous and fast-growing’ cultivar, and we may add to this that it is a most attractive plant, finer in foliage and smaller in flower than E. × nymansensis. Seamus O’Brien (pers. comm. 2018) reports that a dwarf form of E. × intermedia grows in Mount Usher garden, County Wicklow, Ireland, where it has reached a lofty height of 1.5 m in 40 years. It has never flowered, which is surely a testament to Irish patience.