Ulmus 'Hillieri'

Ulmus 'Hillieri'
'Hillieri' in Stanmer Park Arboretum, Brighton, summer, c.2005
Genus	Ulmus
Cultivar	'Hillieri'
Origin	Winchester, England

The elm cultivar Ulmus 'Hillieri' arose from a chance seedling at Hillier's Pitt Corner nursery near Winchester, England, in 1918,^[1] and was marketed from 1928 as Ulmus hillieri,^[2] a name accepted by Christine Buisman in her 1931 labelling of a specimen in France. Since at least 1944 the tree has been determined a form of Ulmus × hollandica, its designation at Kew Gardens, in Green,^[3] and in later Hillier catalogues.^[4] In 1940, 'Hillieri' was noted as being a hybrid of uncertain origin.^[5] Krüssmann notes that for a time the tree was listed by Hilliers as U. × hillieri.^[6]

Not to be confused with Ulmus 'Jacqueline Hillier', which also has a shrubby habit but much smaller leaves.

'Hillieri' is a graceful, compact, slow-growing miniature tree rarely > 1.2 m in height,^{[note 1]} widely branched and bearing weeping branches.^[6] The small leaves (5 – 7 cm by 2.5 – 3 cm^[7]) turn crimson and yellow in favourable autumns,^[1] a feature of at least one Japanese Elm cultivar, 'Jacan'. The 'vivid scarlet' of the autumn leaves was noted (1940) as being a unique colouring for elms.^[5]

• 
  'Hillieri' in Stanmer Park Arboretum, spring
• 
  Fruit of same

The degree of the tree's susceptibility to Dutch elm disease (DED) is unknown. It has been noted that shrub-elms are usually less prone to infection.^[8]

A specimen stood in the Arboretum national des Barres, Nogent-sur-Vernisson, France, in the 1930s.^[7] 'Hillier' was introduced to the US in 1954 as Ulmus hillieri.^[9] An old low shrub-elm in Stanmer Park Arboretum, Brighton (2018, now storm-damaged), planted in the winter of 1965-6, with level rather than pendulous branching and leaves closely matching 'Hillieri' herbarium specimens in Kew Herbarium^[10] and the Arboretum national des Barres,^[7] was said (2018) by Hillier Nurseries, who supplied many elms to the arboretum, to be 'Hillieri',^[11] though it is about 4 m tall and lacks crimson autumn colour. Dutch authorities who examined the tree in 2010 conjectured Japanese Elm hybrid.^[12]

A tree cultivated in Denmark as Ulmus × hollandica 'Hillieri' or Dukke-elm (:Doll's elm) appears from photographs to be U. 'Jacqueline Hillier'.^[13] A tree in the Arboretum Volčji Potok, Slovenia, labelled Ulmus × hollandica 'Hillieri', has leaves much smaller than those of 'Hillieri', and may be a form of dwarf Ulmus parvifolia.^[14][15]

• Ulmus hillieri Hort.: Hillier & Sons, Winchester, England. Cat. 38T, p. 52, 1928.