Ulmus parvifolia 'Zettler' (selling name Heritage)[1] is a Chinese Elm cultivar cloned by Earl Cully from a tree growing near Jacksonville, Illinois, and patented in 1999.
[2] It is one of a small number of American lacebark elm introductions selected for their cold hardiness (USA zone 4 tolerant), others including 'King's Choice', 'Hallelujah', 'Glory' and 'Matthew'.
Heritage has a strong, upright "medium oval" habit and excellent branching structure, bearing deep green glossy foliage that turns to an attractive autumn colour in some years.
[2] The tree attains a height and width of 50 ft by 50 ft.[3] The species and its cultivars are highly resistant, but not immune, to Dutch elm disease, and unaffected by the Elm Leaf Beetle Xanthogaleruca luteola.
[4] Heritage was selected from over 20,000 seedlings in 1975, and subsequently proved to be one of the hardiest Chinese or Lacebark Elms available in the United States, surviving −33 °C (−27 °F) in Illinois during the winter of 1989 without sustaining any damage whatsoever.