'William Penn' is an evergreen barberry with a graceful, upright, arching form that grows about 4 feet tall and 4 to 6 feet wide. It has clusters of bright yellow spring flowers, which are followed by dark red, torpedo-shaped berries that persist into winter and are enjoyed by birds. Leaves are an elongated oval, with slightly toothed margins, and are a dark green. Add it to the shrub or foundation border, or mixed in with ornamental grasses for winter interest. There are some 'William Penn' planted at the Concord Lift Station on Concord Avenue and California Street.
Grow in well drained soil and full sun; will tolerate part shade, though the leaves will lose some color intensity. Tolerates a wide range of soil types, including dry soils; does not tolerate wet soils. See guide for planting instructions. Barberry does not fair well when sheared, but selective pruning in late winter can maintain a nice form and convenient size. See guide for pruning tips.