'Sunburst' hypericum at Arnold Arboretum in Boston

Our native golden St. John’s wort (Hypericum frondosum) deserves more planting space in U. S. gardens (USDA hardiness zones 5-8). ‘Sunburst’ is the leading cultivar and exhibits superior traits over the species.

Golden St. John’s wort forms a small, dense growing deciduous shrub, noted for its showy golden yellow flowers and attractive blue-green foliage. Sunburst grows more compact at 2-3 feet tall and wide, and rarely requires pruning. Leaves are 2 ½ to 3 inches long.

‘Sunburst’ sports slightly larger 2- inch wide flowers which blooms over 3-4 weeks starting in late June. Each bright yellow, 5-petaled flower possesses numerous pincushion-like stamens in the center. Flowers are borne on new wood, and are not threatened by sudden cold temperature snaps in the spring. 

Autumn leaves turn an average yellow before dropping and tend to be evergreen in warmer climes. After two years in the garden, Sunburst demonstrates good heat and drought tolerances in the Southern Appalachian region (USDA zones 6 and 7).

In the autumn small reddish brown fruit capsules form that persist well into winter. Stems exhibit cinnamon colored exfoliating bark in winter.

Disease and insect problems are minimal if properly sited in well-drained soil under full sun (north of zone 7) and in partial shade further south. It grows  well in slightly alkaline limestone-based soils.