Lutèce (elm hybrid)

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Ulmus Lutèce ™
Hybrid parentage
Plantyn x (U. minor Bea Schwarz x U. minor Bea Schwarz selfed)
Cultivar
Lutèce ™
Origin
Wageningen, The Netherlands

One of the last Dutch hybrids to be released, Lutèce ™ is a complex fourth generation tree with an ancestry comprising six varieties of Field Elm U. minor, the Exeter Elm (a curious variety of the Wych Elm U. glabra: var. Exoniensis), and a frost-resistant selection of the Himalayan Elm U. wallichiana. Originally known simply as No. 812, it proved immune to Dutch elm disease when inoculated with unnaturally high doses of the causal fungus Ophiostoma novo-ulmi. Unlike its immediate predecessor Columella, it also developed a more natural, rounded shape similar to the native Field Elm. However, 812 was not commercially promoted by the Dutch owing to fears that it may prove susceptible to Coral Spot fungus Nectria cinnabarina.

The patent for 812 was purchased by the French Institut Nationale pour la Recherche Agronomique (INRA), which subjected the tree to 20 years of field trials in the Bois de Vincennes, Paris, before releasing it for sale in 2002 as Lutèce, the French derivation of Lutetia, the ancient Roman name for the settlement that later became the capital of France.

In trials in southern England, the tree has proven very hardy, tolerant of sea winds and ground waterlogged during winter. Fast growing on moist, well-drained soils, gaining an average of 80 cm per annum, it commences flowering in late March when aged six years. The coarsely-toothed leaves appear relatively late, in early May, and are up to 10 cm long, bright green, with a rough upper surface. Not yet 30 years old, the ultimate size of the hybrid remains unknown but, given its ancestry, should reach at least 30 m in height.

Lutèce ™ is now being established in hedgerows across France. In England, over 3000 have been planted on the Isle of Wight by the Island2000 Trust, and in lower concentrations on the mainland, mostly by members of Butterfly Conservation in the hope it will host the White-letter Hairstreak butterfly Satyrium w-album, a monophagic species that remains in serious decline as a consequence of Dutch elm disease. The tree is not known to have been introduced to North America or Australasia.

[edit] References

• Brookes, A. H. (2006). An evaluation of disease-resistant hybrid and exotic elms as larval host plants for the White-letter Hairstreak Satyrium w-album, Part 1. Butterfly Conservation. Lulworth, UK.
• Pinon, J. (1997). New hope for elm trees (in French). Technologies France, No. 39. ADIT. France.