More Images ULMUS ‘FRONTIER’, Frontier Elm Hardiness Zone: 4 Prices by Size: 1 1/2 in. Cal. , W.B - $50.00 2 in. Cal. , W.B - $80.00 2 1/2 in. Cal. , W:B - $95.00 3 in. Cal., W.B - $125.00 [Your browser doesn't support IFrames. Click here to find the USDA hardiness zone for your zipcode.]