A superior selection from the American hybrid cultivar

Cultivar

A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

 Ulmus 'Coolshade', 'Improved Coolshade' was patented and released by the Sarcoxie Nurseries in 1958.

Pests and diseases

Although reputedly resistant to Dutch elm disease

Dutch elm disease

Dutch elm disease is a disease caused by a member of the sac fungi category, affecting elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, the disease has been accidentally introduced into America and Europe, where it has devastated native...

, it had not been (by 1995) widely tested .

Cultivation

'Improved Coolshade' was noted for its drought tolerance. It is not known whether the tree remains in cultivation in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, nor whether it was introduced to Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 or Australasia

Australasia

Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

.