FL 506


FL 506 Castellaccio 2010

FL 506 Castellaccio 2010

[U. chenmoui x [(U. glabra x U. minor) x U. minor]]


Istituto per la Protezione delle Piante, Florence, Italy






FL 506 is a full sibling of Morfeo (FL 509), with which it is inevitably compared.  Its 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.  Having been known familiarly for some time as “Morfeo’s Brother”, it seems that if patented the tree may take the name “Fantasus” (one of the brothers of Morpheus).  FL 506 was introduced to Britain in the spring of 2012. 


In inoculation trials at Antella, Florence, FL 506 exhibited defoliation of 8.50%, and dieback of 0.17%.  This compares with Morfeo’s scores of 4.67% and 0% – clearly a little less good, but still at the top of the range referred to as 5/5 in French and Dutch testing. 


In adaptation trials in central Italy, FL 506 achieved a slightly greater annual height increment and a lesser girth increment than Morfeo on the fertile soil of the relatively temperate site at Castellaccio (Umbria).  At the cold Feudozzo and hot Mediterranean Marsiliana sites, FL 506’s performance was considerably worse than that of Morfeo. 

Although the two clones share identical parentage, their characters are quite distinct.  Morfeo inherits most obviously from U.x Hollandica, the so-called Dutch elm which is in fact a natural hybrid of wych elm and field elm.  FL 506 seems to express the U. glabra (wych elm) genes within x Hollandica.


FL 506 Foliage 2

FL 506 foliage 2

FL 506 Foliage 1

FL 506 foliage 1

The FL 506 leaf is larger than that of Morfeo, and has less of the down which gives Morfeo’s foliage a glaucous cast in certain lights.  Vigorous leaves differ in shape, sometimes recalling cherry, but often developing a breadth towards the tip which is reminiscent of wych elm.  On mature branches of moderate vigour, FL 506 foliage is held more elegantly than that of Morfeo, with a lesser tendency to distort during the season.  Branching is comparatively straight and angular.


As with some other clones, very small plants received from Italy occasionally have some flower because the Italian winter propagation utilises wood from relatively mature trees.  As the plant adapts to growth on its own roots, flowering ceases, presumably until its fourth year.  Synchronicity with wych elm flowering for the benefit of the White-letter Hairstreak butterfly can be assumed to be optimal, as with Morfeo.


The large and heavy leaves of FL 506 seem thoroughly unsuited to softwood propagation, and the clone is no more inclined to produce secondary shoots from axial buds than is Morfeo.  Winter hardwood propagation is assumed to be straightforward. 


The greater disease resistance and adaptability of Morfeo may seem to relegate FL 506 to the position of permanent understudy, perhaps useful for bringing an advisable element of genetic variation to plantings centred around the better-known clone.  Nevertheless, personal observation of M’s brother suggests that it deserves more prominence in its own right.  Quite unlike Morfeo, it has the habit of a woodland tree (and would benefit from the protection of woodland planting in its early years, given its large juvenile leaves).  In short, it is quite close in style to wych elm, and has some claim to the place left in the woods by that species.

Wikipedia reference: n/a