Leaves are atypically dark green, small, and closely spaced on branches (have short internodes) on Chinese elms, Ulmus parvifolia, (left and background) after the annual application of paclobutrazol (Clipper) plant growth regulator (PGR) for 8 years to suppress shoot growth into overhead power lines. Trees not under power lines (right) were not treated and do not show similar symptoms. Credit: Laurence R. Costello, UCCE San Francisco-San Mateo
