St John's Wort (Hypericum spp) is a pretty perennial shrub, typically with bright yellow flowers followed by distinctive clusters of berries. There are hundreds of species, some with medicinal properties, and many native to the US where it's also referred to as goatweed and Klanath weed.
A couple of the most popular native species are Hypericum prolificum, or shrubby St John's Wort and Hypericum densiflorum (bushy St. John's wort). These plants will tolerate various conditions, so they are among the best perennials for low-maintenance gardening.
