Hypericum, or St. John's wort, is a small shrubby perennial covered in cheerful golden-yellow flowers through summer, each with a puff of showy stamens at the center. It builds into a tidy mound roughly two feet tall and wide.

Give it sun to part sun and well-drained soil; once rooted in, it handles heat and dry spells without complaint. Use it mid-border or massed on a bank. Butterflies and other pollinators visit steadily while it's in bloom.