The elm cultivar Ulmus minor 'Bea Schwarz' was cloned (as No. 62) at Wageningen in the Netherlands, by the elm disease committee, from a selection of Ulmus minor found in France in 1939. Specimens of the tree grown in the UK and the United States are sometimes incorrectly listed as Ulmus × hollandica (after Fontaine).
Description The leaves are ovoid to oval (6 to 10 cm), emerging more or less purple-red; the underside is pillose. Sheet labelled Ulmus 'Bea Schwarz', Baarn, 1948; Sheet labelled Ulmus 'Bea Schwarz', Baarn, 1949; "Herbarium specimen DOV0038308". Delaware State University, Claude E. Phillips Herbarium. Sheet labelled U. × hollandica 'Bea Schwarz'; leaves specimen; "Herbarium specimen DOV0038308". Delaware State University, Claude E. Phillips Herbarium. Sheet labelled U. × hollandica 'Bea Schwarz'; flowers specimen The tree is considered of poor growth and shape if grafted on U. × hollandica rootstock.Photograph of free-standing 'Bea Schwarz' elm, . Nowadays it is sparsely grown on its own rootstock.
Pests and diseases Not resistant to the second, more virulent, strain of Dutch elm disease, (O. novo-ulmi), but more resistant to Coral Spot fungus Nectria cinnabarina than its forebear 'Christine Buisman'.
Cultivation Commercial production was discontinued in the Netherlands soon after its release in 1948.Went, J. C. (1954). Tijschr. Plantenziekten 60: 109-127, 1954. Nevertheless, its moderate resistance to Dutch elm disease saw it, or its selfed progeny, successfully used in later Dutch hybridizations, notably 'Nanguen' = . 'Bea Schwarz' was later propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire from 1967 to 1977, when production ceased with the advent of the more virulent form of Dutch elm disease.Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.Hillier & Sons Sales inventory 1962 to 1977 (unpublished). A specimen was planted on its own rootstock in Dennenlaan, Loosdrecht (2019), as part of Wijdemeren City Council's elm collection.Netherlands Plant Collection: Iepen, Ulmus, Netherlands Plant Collection
Notable trees The largest known examples in the UK grow along Crespin Way, Hollingdean, Brighton; planted in 1964, they measured 19 m high by 50 cm d.b.h. in 2009.Johnson, O. (2011). Champion trees of Britain & Ireland, p.167. Kew Publishing, Kew London.
Hybrid cultivars 'Nanguen' = , 'Clusius', 'Lobel', (all from crossings with clone '336', 'Bea Schwarz' selfed), Ulmus 'Amsterdam' (possibly from an open pollination of 'Bea Schwarz' and sometimes called Ulmus minor 'Amsterdam' in the Netherlands).Tijdgat, M. (2020): Ulmus – Gebruikswaarde- en sortimentsonderzoek in de praktijk. Dendroflora Nr. 56-2020, p.73 Koninklijke Vereniging voor Boskoopse Culturen & Nederlandse Dendrologische Vereniging
Etymology The tree is named for Bea Schwarz, the Dutch phytopathologist who identified the Asian microfungus known as Ophiostoma ulmi, one of the causative agents of Dutch elm disease, in the 1920s.
Accessions North America Arnold Arboretum, US. Acc. nos. 151–61, 276–62 Holden Arboretum, US. Acc. no. 57–1243 Longwood Gardens, US. Acc. no. 1967–0876
Europe Brighton & Hove City Council, UK. NCCPG Elm Collection. Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 1275
Nurseries Europe Noordplant , Glimmen, Netherlands.
References