Bushy St. John's Wort grows where the ground stays damp: along pond banks, seepage slopes, stream margins, and wet meadows across eastern North America from the coastal plain to the mountains. At its best it reaches 7 feet tall and 6 feet wide, forming a dense, arching mass that erupts in clusters of small yellow flowers each summer. In North Carolina it turns up in coastal and mountain habitats, rarer in the Piedmont.

It blooms on new wood, so a hard pruning in early spring keeps the plant shapely and encourages the heaviest flowering. Despite its preference for moist ground, it adapts readily to average garden soil with reasonable drainage. Plant it in groups at a rain garden edge, along a naturalistic border, or as an informal hedge. Bees find it reliably, and it earns the rare distinction of performing well in the root zone of black walnut.