[U. chenmoui x [(U. glabra x U. minor) x U. minor]]
Istituto per la Protezione delle Piante, Florence, Italy
FL 509 is one of several crosses obtained during the later stages of the Italian hybridisation programme using U. chenmoui, a small elm from the eastern Chinese provinces of Anhui and Jiangsu. The female parent arose from the Dutch crossing of an English U. x hollandica (“Dutch elm”), with a French U. minor (field elm) from the Barbier Nursery, Orleans. The clone was named Morfeo in 2010.
In inoculation trials conducted at Antella, Florence, in 2000, Morfeo exhibited defoliation of only 4.67%, and dieback of 0%. It is therefore among the most resistant trees created by the Italian programme.
Morfeo’s habit in Italy is essentially upright, while in England the leading shoot has a tendency to grow away from the vertical. The plant generally forks in its second or third year. The current year’s growth is markedly stout and sideshoots are absent or rare. In adaptation trials held in Italy, Morfeo was one of the slower growing trees in a group of 24 highly resistant clones, though its growth is fast by comparison with most native species. Height and girth increments are well balanced and root development is strong, so that the tree quickly develops excellent stability. Some specimens develop patches of corky bark (a trait particularly marked in U. hollandica), and this becomes more frequent as the tree matures. Branch crotches are strong, without bark inclusion. Root suckers are produced.
Adult leaves have a good resemblance to field elm in terms of range of shape, although they are somewhat larger. Stalks are short. The absence of U. pumila or U. davidiana ancestry is obvious. Leaves on vigorous shoots are large and coarse, though this fault is less apparent from a distance.
The colour of the leaves is strongly influenced by the tree’s Chenmoui genes. Although the foliage is mid green, its dense pubescence gives it a glaucous or even a greyish cast in certain lights (the photo shows Morfeo leaves above, Accolade below). Morfeo is early to come into leaf, and towards the end of the summer the foliage can have a tired appearance, with discolouration and recurvature of the leaf distorting or concealing its shape. This is less apparent in older specimens making less vigorous growth, and in the interior of the canopy. Autumn colours include brown, red and purple – completely different from the muted yellow of native elm.
Morfeo enters into flower from about its fourth year. Flowers and seeds are comparatively large. Flowering is synchronic with that of wych elm, formerly the main larval host plant of the endangered White-letter Hairstreak butterfly, Satyrium w-album. Morfeo has therefore been identified by Butterfly Conservation as a potential replacement host for this Biodiversity Action Plan species.
Morfeo roots readily from hardwood cuttings taken in late winter from vigorous year-old shoots and given bottom heat of 18 degrees. Softwood propagation is possible, but cuttings have a tendency to rot in humid conditions because the down on stems and leaves holds excessive moisture. The axial buds of internodal softwood cuttings are very slow to break.
Morfeo’s excellent disease resistance and stability entitle it to be regarded as one of the best modern elm clones. Further qualities are its adaptability to a range of soils including chalk, early leafing, good leaf shape, characterful bark, suckering, and ease of winter hardwood propagation. In combination these advantages tend to outweigh deficiencies such as the cold tone of the foliage and the tendency of young plants to grow away from the vertical (fairly easily corrected).
Morfeo’s ultimate appearance seems likely to be reminiscent of U. x hollandica; open-crowned and rustic.
Wikipedia reference: http://en.wikipedia.org/wiki/Ulmus_’Morfeo’