''Ulmus'' 'Clusius' is a Dutch

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

elm Elms are deciduous and semi-deciduous trees comprising the genus ''Ulmus'' in the family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical- montane regions of North America and Eurasia, ...

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

raised at the Dorschkamp Research Institute for Forestry & Landscape Planning,

Wageningen Wageningen () is a Municipalities of the Netherlands, municipality and a historic city in the central Netherlands, in the province of Gelderland. It is famous for Wageningen University, which specialises in life sciences. The municipality had a ...

, as clone 568 and released to commerce in 1983. 'Clusius' was derived from a crossing of the same Dutch clones that produced the fastigiate 'Lobel' released in 1973: '202' ( 'Exoniensis' × ''U. wallichiana'') and '336' ( 'Bea Schwarz' selfed).

Description

The tree has a broader crown than its sibling's, whilst the generally

obovate The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets) ...

leaves, < 11 cm long by 7 cm wide, are less acuminate at the apex and a lighter green. The seed is near the notch (apex) of the

samara Samara, formerly known as Kuybyshev (1935–1991), is the largest city and administrative centre of Samara Oblast in Russia. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with a population of over 1.14 ...

. Like 'Lobel', the tree flushes markedly later than most other elms, and is rarely in full leaf before mid-May.

Pests and diseases

Whilst the resistance of 'Clusius' to Dutch elm disease proved marginally greater than that of its Dutch predecessors, rated 4 out of 5,Heybroek, H. M., Goudzwaard, L, Kaljee, H. (2009). ''Iep of olm, karakterboom van de Lage Landen'' (:Elm, a tree with character of the Low Countries). KNNV, Uitgeverij. it has been eclipsed by later developments such as . Consequently, sales in the Netherlands declined from over 8,000 in 1979 to 600 in 2004.

Cultivation

While 'Clusius' remains for sale in Europe, its planting where the disease remains prevalent cannot be recommended. In the UK, 'Clusius' is present in the National Elm Collection, Brighton and Hove, and in Edinburgh (two in Abbeyhill, opposite

Holyrood Palace The Palace of Holyroodhouse ( or ), commonly known as Holyrood Palace, is the official residence of the British monarch in Scotland. Located at the bottom of the Royal Mile in Edinburgh, at the opposite end to Edinburgh Castle, Holyrood has s ...

, and one in The Meadows). Six specimens were planted in front of the library,

Keele University Keele University is a Public university#United Kingdom, public research university in Keele, approximately from Newcastle-under-Lyme, Staffordshire, England. Founded in 1949 as the University College of North Staffordshire, it was granted uni ...

, Staffordshire, c.2010.'Clusius' between library and Union Square, Keele University, Staffordshire
/ref> 'Clusius' featured in New Zealand government trials during the 1990s at the Hortresearch station,

Palmerston North Palmerston North (; , colloquially known as Palmerston or Palmy) is a city in the North Island of New Zealand and the seat of the Manawatū-Whanganui region. Located in the eastern Manawatū Plains, the city is near the north bank of the Manaw ...

, but is not known to have been introduced to North America. File:Treinstation, Medemblik.jpg, 'Clusius',

Medemblik Medemblik () is a municipality and a city in the Netherlands, in the province of North Holland and the region of West Friesland (region), West-Frisia. It lies immediately south of the polder and former municipality of Wieringermeer. History Med ...

train station (2013) File:Keele University, Union Square from the Library steps - geograph.org.uk - 4312474.jpg, Six 'Clusius' in Union Square, Keele University (2015) File:Pipework installations at Keele University (4) - geograph.org.uk - 5683151.jpg, Same, 2018

Etymology

The cultivar is named for

Carolus Clusius Charles de l'Écluse, L'Escluse, or Carolus Clusius (19 February 1526 – 4 April 1609), seigneur de Watènes, was an Artois doctor and pioneering botanist, perhaps the most influential of all 16th-century scientific horticulturists. Life C ...

, a Dutch naturalist of the

Renaissance The Renaissance ( , ) is a Periodization, period of history and a European cultural movement covering the 15th and 16th centuries. It marked the transition from the Middle Ages to modernity and was characterized by an effort to revive and sur ...

Accessions

;Europe *

Arboretum de La Petite Loiterie The Arboretum de la Petite Loiterie (16 hectares) is a young arboretum located in Le Sentier, Monthodon, Indre-et-Loire, Centre-Val de Loire, France. It is open a few days per month; an admission fee is charged. The arboretum was conceived in 198 ...

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Monthodon Monthodon () is a commune in the Indre-et-Loire department in central France. Population Sights * Arboretum de la Petite Loiterie See also *Communes of the Indre-et-Loire department The following is a list of the 272 communes of the In ...

, France. No details available *

Grange Farm Arboretum The Grange Farm Arboretum is a small private arboretum comprising 3 hectares accommodating over 800 trees, mostly native and ornamental species or cultivars, notably oaks, ashes, walnuts and elms, growing on a calcareous loam.Ostler, J. (2009) ...

Sutton St James Sutton St James is a village and civil parish in the South Holland, Lincolnshire, South Holland district of Lincolnshire, England, about south-west of Long Sutton, Lincolnshire, Long Sutton. Lying in the Lincolnshire Fens, Sutton St James did ...

, Spalding, Lincs., UK. Acc. no. 817. *

Sir Harold Hillier Gardens The Sir Harold Hillier Gardens is an arboretum comprising 72 hectares (180 acres) accommodating over 42,000 trees and shrubs in about 12,000 taxa, notably a collection of oaks, camellia, magnolia and rhododendron. The Gardens are located north ...

Ampfield Ampfield is a village and civil parish in the Borough of Test Valley in Hampshire, England, between Romsey, Eastleigh, and Winchester. It had a population at the 2001 census of 1,474, increasing to 1,583 at the 2011 Census. The civil parish of ...

Romsey Romsey ( ) is a town in the Test Valley district of Hampshire, England. The town is situated northwest of Southampton, southwest of Winchester and southeast of Salisbury. It sits on the outskirts of the New Forest, just over northeast of ...

Hampshire Hampshire (, ; abbreviated to Hants.) is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Berkshire to the north, Surrey and West Sussex to the east, the Isle of Wight across the Solent to the south, ...

, UK. Acc. no: 2019.0441 *

Wijdemeren City Council Wijdemeren () is a municipality in the Netherlands, in the province of North Holland, on the western border of the Gooi region. Wijdemeren contains many lakes, including ''Spiegelplas'' and ''Ankeveense Plassen'' in the north(east) and ''Loosdrech ...

, Netherlands. Elm Collection. planted mainly in Kortenhoef since 2006.

Nurseries

*Noordplan

Glimmen Glimmen is a village in the northeastern Netherlands. It is located in the municipality of Groningen, about 10 kilometres from the city. It had a population of around 1,342 in 2021. The river Drentsche Aa flows past the village, nearby the ''Huis t ...

, Netherlands. *Barcham Trees PLC,

Ely, Cambridgeshire Ely ( ) is a cathedral city and civil parish in the East Cambridgeshire district, in Cambridgeshire, England, northeast of Cambridge, southeast of Peterborough and from London. At the 2021 United Kingdom census, 2021 census, the built-up a ...

https://www.barchampro.co.uk/store/products/ulmus-clusius]

References

{{Elm species, varieties, hybrids, hybrid cultivars and species cultivars , state=collapsed Hybrid elm cultivar Ulmus articles with images Ulmus