Summary
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. However, specimens of the tree grown in the UK and the United States are falsely treated as Ulmus × hollandica (after Fontaine [1]).
| Ulmus minor 'Bea Schwarz' | |
|---|---|
 'Bea Schwarz', Amsterdam. | |
| Cultivar | 'Bea Schwarz' |
| Origin | Netherlands |
Description edit
The leaves are ovoid to oval (6 to 10 cm), emerging more or less purple-red; the underside is pillose.[1][2] The tree is considered of poor growth and shape if grafted on U. × hollandica rootstock.[3] Nowadays it is sparsely grown on its own rootstock.
Pests and diseases edit
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 edit
Commercial production was discontinued in the Netherlands soon after its release in 1948.[4][5][6] Nevertheless, its moderate resistance to Dutch elm disease saw it, or its selfed progeny, successfully used in later Dutch hybridizations, notably 'Nanguen' = Lutèce. '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.[7][8]
!['Bea Schwarz' on the left with later replacements on the right. Noordzijde, Sloterplas, Amsterdam, 2012.[9]](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Bea_Schwarz-iepen_bij_de_Sloterplas.jpg/120px-Bea_Schwarz-iepen_bij_de_Sloterplas.jpg)
Notable trees edit
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.[10]
Hybrid cultivars edit
- 'Nanguen' = Lutèce, '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).[11]
Etymology edit
The tree is named for Bea Schwarz, the Dutch phytopathologist who identified the Asian fungus known as Dutch elm disease in the 1920s.
Accessions edit
North America edit
- Arnold Arboretum, US. Acc. nos. 151–61, 276–62
- Holden Arboretum, US. Acc. no. 57–1243
- Longwood Gardens, US. Acc. no. 1967–0876
Europe edit
- Brighton & Hove City Council, UK. NCCPG Elm Collection.[12]
- Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 1275
- Netherlands Plant Collection Ulmus, Wijdemeren, North Holland, Netherlands, planted on its own rootstock 2019, Location Dennenlaan, Loosdrecht[13]
Nurseries edit
Europe edit
- Noordplant [2], Glimmen, Netherlands.
References edit
- ^ a b F. J., Fontaine (1968). "Ulmus". Dendroflora. 5: 37–55. Retrieved 30 August 2017.
- ^ "Herbarium specimen - L.1586828". Botany catalogues. Naturalis Biodiversity Center. Sheet labelled Ulmus 'Bea Schwarz', Baarn, 1948; "Herbarium specimen - L%20%200940206". Botany catalogues. Naturalis Biodiversity Center. 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
- ^ Photograph of free-standing 'Bea Schwarz' elm, [1].
- ^ Heybroek, Hans M. (1983). Burdekin, D.A. (ed.). "Resistant elms for Europe" (PDF). Forestry Commission Bulletin (Research on Dutch Elm Disease in Europe) (60). London: HMSO: 108–113.
- ^ Heybroek, H.M. (1993). "The Dutch Elm Breeding Program". In Sticklen, Mariam B.; Sherald, James L. (eds.). Dutch Elm Disease Research. New York, USA: Springer-Verlag. pp. 16–25. ISBN 978-1-4615-6874-2. Retrieved 26 October 2017.
- ^ Went, J. C. (1954). Tijschr. Plantenziekten 60: 109-127, 1954.
- ^ Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.
- ^ Hillier & Sons Sales inventory 1962 to 1977 (unpublished).
- ^ "Noordzijde near sloterplas". Retrieved 21 February 2019.
- ^ Johnson, O. (2011). Champion trees of Britain & Ireland, p.167. Kew Publishing, Kew London. ISBN 978-1-84246-452-6
- ^ Tijdgat, M. (2020): Ulmus – Gebruikswaarde- en sortimentsonderzoek in de praktijk. Dendroflora Nr. 56-2020, p.73 Koninklijke Vereniging voor Boskoopse Culturen & Nederlandse Dendrologische Vereniging
- ^ "List of plants in the {elm} collection". Brighton & Hove City Council. Retrieved 23 September 2016.
- ^ Netherlands Plant Collection: Iepen, Ulmus