The

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 dif ...

elm

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

''Ulmus × intermedia'' 'Coolshade' is an American

cloned from a crossing of the Slippery, or Red, Elm ''

Ulmus rubra ''Ulmus rubra'', the slippery elm, is a species of elm native to eastern North America. Other common names include red elm, gray elm, soft elm, moose elm, and Indian elm. Description ''Ulmus rubra'' is a medium-sized deciduous tree with a spre ...

'' (female parent) and the Siberian Elm ''

Ulmus pumila ''Ulmus pumila'', the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm' ('' Ulmus parvifolia''). ''U. pumila'' has been widely cultivated throughout Asia, No ...

'' at the Sarcoxie Nurseries, Sarcoxie,

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

, in 1946. At Arnold Arboretum, where there was a specimen, herbarium material was labelled ''Ulmus pumila'' 'Coolshade'.

Description

'Coolshade' has rapid, stocky growth with a compact crown resistant to breakage under ice and snow. Its foliage is a very dark green.Bean, W. J. (1981). ''Trees and shrubs hardy in Great Britain'', 7th edition. Murray, London. There appears to be little evidence of ''Ulmus rubra'' ingression in the Arnold Arboretum 1960 leaves specimens labelled ''Ulmus pumila'' 'Coolshade', suggesting that its hybridity may have been questioned there.bioportal.naturalis.nl, specimen L.1582543
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Pests and diseases

Reputedly tolerant of

Dutch elm disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into Americas, America ...

, 'Coolshade' has not been tested by inoculation to determine the degree of resistance.

Cultivation

'Coolshade' was raised to create a disease-resistant tree that would not suffer the storm damage frequently sustained by the weak-wooded ''U. pumila''. The tree was introduced to the UK in the 1960s but no longer survives there.

Cultivars

* 'Improved Coolshade'

Accessions

North America

* Arnold Arboretum, US. Acc. no. 561–48

References

{{DEFAULTSORT:Ulmus x intermedia 'Coolshade' Ulmus × intermedia cultivar Ulmus articles missing images Ulmus