Ulmus minor 'Bea Schwarz' explained
| Ulmus minor 'Bea Schwarz' |
| Cultivar: | 'Bea Schwarz' |
| Origin: | Netherlands |
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]).
Description
The leaves are ovoid to oval (6 to 10 cm), emerging more or less purple-red; the underside is pillose.[2] [3] The tree is considered of poor growth and shape if grafted on U. × hollandica rootstock.[4] 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.[5] [6] [7] 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.[8] [9]
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.[10]
Hybrid cultivars
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
Europe
Nurseries
Europe
Notes and References
- F. J.. Fontaine. Ulmus. Dendroflora. 1968. 5. 37–55. 30 August 2017.
- F. J.. Fontaine. Ulmus. Dendroflora. 1968. 5. 37–55. 30 August 2017.
- 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
- Photograph of free-standing 'Bea Schwarz' elm, http://www.ca.uky.edu/agcollege/plantpathology/vaillanc/for410/Dutch%20Elm%20Disease/BASIC/DED/CORE/00/00/F7.HTML.
- D.A.. Burdekin. Forestry Commission Bulletin (Research on Dutch Elm Disease in Europe). 60. Heybroek. Hans M. . HMSO. London. 1983. Resistant elms for Europe. 108–113.
- Book: Heybroek. H.M.. Sticklen. Mariam B.. Sherald. James L.. Dutch Elm Disease Research. 1993. Springer-Verlag. New York, USA. 16–25. 26 October 2017. The Dutch Elm Breeding Program. https://books.google.com/books?id=avvxBwAAQBAJ&pg=PA16. 978-1-4615-6874-2.
- 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).
- Johnson, O. (2011). Champion trees of Britain & Ireland, p.167. Kew Publishing, Kew London.
- https://edepot.wur.nl/545143 Tijdgat, M. (2020): Ulmus – Gebruikswaarde- en sortimentsonderzoek in de praktijk. Dendroflora Nr. 56-2020, p.73 Koninklijke Vereniging voor Boskoopse Culturen & Nederlandse Dendrologische Vereniging
- Web site: List of plants in the collection. Brighton & Hove City Council. 23 September 2016.
- https://wijdemeren.cobra360.nl/index.php?@iepen Netherlands Plant Collection: Iepen, Ulmus
