japonica 'Prospector' was originally treated as a cultivar of Wilson's elm U. wilsoniana Schneid., a species sunk as Ulmus davidiana var.

[3] 'Prospector' was introduced to the UK in 2009, by Hampshire & Isle of Wight Branch, Butterfly Conservation, as part of an assessment of DED-resistant cultivars as potential hosts of the endangered White-letter Hairstreak.

In trials in California, the tree exhibited a singular sensitivity to boron concentrations of > 200 ppm in the soil, causing marginal necrosis on the leaves.

In trials conducted by the University of Minnesota, 'Prospector' was appreciated for its extraordinary vigour but faulted for the weakness of its wood, notably stem breakage owing to bark inclusion.

'Prospector' was introduced to Europe by Butterfly Conservation in 2009 as part of its elm trials programme in Hampshire but has exhibited very slow growth, its stem increasing by just 2 mm in diameter at breast height per annum.