Carpinus betulus 'Columnaris Nana' (Dwarf Columnar European Hornbeam)
Given no pruning, forms a dense, dwarf, upright tree . It is useful as a walkway or border focal point or as an edging feature. A diminutive hedge could be another landscape option, with the larger-than-usual buds adding to its winter interest. Rarely available in the trade still, but very easy to grow and zero maintenance required other than irrigation.