The 'dwarf' elmcultivarUlmus'Jacqueline Hillier' is an elm of uncertain origin. It was cloned from a specimen found in a private garden in Selly Park, Birmingham, England, in 1966. The garden's owner told Hillier that it might have been introduced from outside the country by a relative. Hillier at first conjectured U. minor, as did Heybroek. Identical-looking elm cultivars in Russia are labelled forms of Siberian Elm, Ulmus pumila, which is known to produce 'JH'-type long shoots. Melville considered 'JH' a hybrid cultivar from the 'Elegantissima' group of Ulmus × hollandica. Uncertainty about its parentage has led most nurserymen to list the tree simply as Ulmus 'Jacqueline Hillier'. 'JH' is not known to produce flowers and samarae, or root suckers. Not to be confused with Ulmus × hollandica 'Hillieri', an older miniature elm from the same nursery.
Description
With time 'JH' makes a large shrub, then a small tree, initially of dense habit, but spreading with age if left unpruned. It bears small, double-toothed scabrid leaves 2.5 cm to 3.5 cm long on densely hairy twigs. In winter its tidy 'herringbone' branches and branchlets proclaim it an elm, despite its shrublike size.
Pests and diseases
Resistance to Dutch elm disease is not known, but is probably academic as the tree is unlikely to attain the height at which it would attract the attention of the bark beetles that act as vectors of the disease. In trials in the United States, 'JH' was found to be virtually unaffected by the Elm Leaf BeetleXanthogaleruca luteola .
Cultivation
'JH' is commonly found in cultivation in Europe and the United States, where it is considered particularly suitable for small gardens, rockeries, low hedges, and bonsai. A hardy tree, it is said to survive temperatures as low as in North America. Despite its dwarf nature and its reputation as a slow-grower, 'JH' is said to grow by in ten years, faster than the dwarf wych elm 'Nana'.
The UKTROBI Champion grows at Talbot Manor in Norfolk, measuring 8 m high by 28 cm d.b.h. in 2008. Another at Exbury Gardens in Hampshire measured 6 m high by 35 cm d.b.h. in 2006 In keeping with the ancient tradition of planting funerary elms to commemorate the dead, specimens of 'Jacqueline Hillier' were planted on either side of the memorial to the dead in the Quintinshill rail disaster, Britain's worst rail disaster, in Rosebank Cemetery, Edinburgh.
Accessions
;North America
Chicago Botanic Garden, Illinois, US. 1 tree in Educational Center Gardens, listed as U. × hollandica 'Jacqueline Hillier'.