Light is the energy source that drives photosynthesis, and matching a plant to the right amount of sunlight is one of the most critical decisions in garden design. A sun-loving lavender planted in deep shade will stretch, refuse to flower, and eventually succumb to fungal disease, while a shade-loving hosta planted in full afternoon sun will scorch, bleach, and wilt within weeks.
The Sun Exposure Guide helps you avoid these costly mismatches by organizing plants into three standard light categories used throughout the nursery industry: full sun (six or more hours of direct sunlight), partial shade (three to six hours, ideally morning sun), and full shade (fewer than three hours of direct light). For each plant, the guide notes whether it prefers morning or afternoon sun, how it performs at the boundary between categories, and whether it needs protection from intense afternoon heat in southern zones. Light needs interact with other growing conditions: a plant that demands full sun in Zone 5 may actually prefer partial shade in Zone 9 where summer temperatures regularly exceed 95 degrees. The guide flags these regional adjustments so you can make confident planting decisions regardless of where you garden.