Ulmus 'Stavast' is a Dutch hybrid elm cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, as clone '622' from the crossing of 'Commelin' with clone '202', itself a hybrid of the Exeter Elm Ulmus 'Exoniensis' and Himalayan Elm Ulmus wallichiana.
The tree is distinguished by its dense root system.
Pests and diseases
'Stavast' has only a moderate resistance to Dutch elm disease, rated 3 out of 5.
'Stavast' has not been in commerce in its own right much. It is retained as a rootstock for grafting, as its dense root system quickly stabilized young trees. It was used as a rootstock for grafting related elms like ‘Dodoens’, ‘Clusius’ and ‘Plantijn’, cultivars now propagated by rooted cuttings.