A low-growing perennial, St. John's Wort is the perfect groundcover to brighten a shady spot. The foliage is chartruese, but turns gold when exposed to more sun. With yellow blooms in midsummer, this perennial is easy to grow and can grow in full shade, part sun, or full sun. 
 
Height: 12" (30cm)
Space: 12-18" (30-45cm)
Light Requirements: Full sun, part shade, full shade
Soil Requirements: Well-draining, rich in organic matter
Zones: 5-7
Bloom season: Spring to midsummer