A hybrid between the two Chilean species, E. glutinosa and E. cordifolia. It is an evergreen tree of erect handsome shape, its foliage being intermediate between that of its parents in the fact that some of the leaves are compound as in glutinosa, whilst others are simple as in cordifolia. They are firm, rather leathery in texture and the compound leaves are mostly trifoliolate, the central leaflet being the largest and 11⁄2 to 31⁄2 in. long by 1 to 11⁄2 in. wide; all have regular marginal teeth, a dark shining upper surface, a paler lower one, and a slight down on both. Young shoots ribbed, downy. The flowers open in August and are pure white, 21⁄2 in. wide; petals four, spreading, overlapping, with uneven margins; stamens numerous with yellow anthers; flower-stalk downy.
This famous cross first arose at Nymans, Handcross, Sussex, from seed sown in 1914, shortly before the death of Ludwig Messel, the founder of the garden. E. cordifolia had first flowered there in 1909 and it is known that seedlings from it were raised in the hope of producing a hardier form. But it may be that in 1914 seed from both the parents was sown and that the cross occurred in both batches. Shortly after the end of the first world war, the late Lt. Col. L. C. R. Messel gave away plants to friends, among them the late Sir Frederick Stern, whose plant, received in 1919, first flowered in September 1922. Others were retained and planted in the garden. Tradition has it that the group in the northeast corner of the garden are some of the original seedlings, their small size being due to the exposed position in which they grow and also, perhaps, to the preponderance of E. glutinosa in their make-up.
Of the plants grown on at Nymans, two were selected as outstanding and were designated ‘Nymans A’ and ‘Nymans B’. The first of these was shown at Vincent Square in August 1924 as ‘Nymansay’, when it received an Award of Merit and two years later a First Class Certificate. The same cross also occurred at Mount Usher, Co. Wicklow, Eire.
E. × nymansensis is usually seen as a slender, erect shrub or small tree which may attain 40 to 50 ft in height. It needs a moist soil and a position protected from searing winds. Given those conditions it will tolerate full sun and indeed will prove shy-flowering if grown in too shady a place. It was badly damaged in a few gardens in the severe winters of 1961-3 but can be considered as hardy and satisfactory except in the more continental parts of eastern and southeastern England. Fortunately, like E. cordifolia, it has no aversion to limy soils. It sets fertile seed, but the seedlings will of course be variable and perhaps slower to flower than plants raised by cuttings or layers from selected parents.