In Italy, 'Plinio' is a rounded tree with a broad crown, the width typically equalling 70% of height, and a short, often bent, trunk. The dark-green leaves are < 6.5 cm long by 3 cm broad and glabrous on both sides, on < 6 mmpetioles.[2][3] Like its compatriot 'San Zanobi', the tree is not possessed of striking autumn colours, the leaves remaining green almost until they fall in late November. The perfect, apetalous wind-pollinated flowers appear in mid March in the UK. The sessilesamarae are round, 17–22 mm in diameter. Seed has exhibited a modest viability of between 10% and 20%.[1]
'Plinio' has a very high resistance to Dutch Elm Disease. In trials conducted by the Istituto per la Protezione delle Piante, Florence, 'Plinio' sustained 7.8% defoliation and 3.9% dieback when inoculated with unnaturally high concentrations of the fungal pathogen, compared with 50% / 35.5% resp. for 'Lobel', and 95% / 100% for 'CNR118', a Field Elm (Ulmus minor) native to Italy.[2]
Fast growing (though slower than its stablemate 'San Zanobi') in Italy, where it commences flowering in its third year. The tree was introduced to the UKbyButterfly Conservation in 2004 and is being evaluated at several sites in Hampshire, where it has been found to be particularly successful on thin dry rendzinas. However, on more fertile soils, the relatively sparse and splaying top growth often exceeds stem and root development.[1]
As of 1 January 2018, the importation of 'Plinio' into the UK from Italy is prohibited, the plant unable to qualify for a phytopassport owing to the prevalence of Elm Yellows in the region of cultivation.[4]
'Plinio' is not known (2016) to have been introduced to North America or Australasia.
^ abcBrookes, A. H. (2020). Great Fontley Elm Trial, 2020 Report. Butterfly Conservation, Lulworth, England.
^ abSantini A., Fagnani A., Ferrini F. & Mittempergher L., (2002) 'San Zanobi' and 'Plinio' elm trees. [1]HortScience 37(7): 1139-1141. 2002. American Society for Horticultural Science, Alexandria, VA 22314, USA
^Santini A., Fagnani A., Ferrini F., Mittempergher L., Brunetti M., Crivellaro A., Macchioni N., Elm breeding for DED resistance, the Italian clones and their wood properties. [2]Invest Agrar: Sist. Recur. For. (2004) 13 (1), 179–184. 2004.
