'Sunburst' is a popular cultivar of shrubby St. Johnswort that, in comparison to the species, features slightly larger flowers (to 2 inches diameter) on a more compact plant (about 3 feet tall). Otherwise, it shares all the characteristics of H. frondosum.
Grow in average, well-drained soils in full sun to part shade. Prefers rich, sandy loams. Tolerant of some drought. Apply mulch around root zone to aid in over-wintering. Plants may suffer tip dieback or die entirely to the ground in harsh winters. When plants die to the ground in winter, the roots often survive and send up new shoots in spring. Flowers bloom on new wood, so winter damage will not adversely affect flowering.