Rhododendrons generally grow best with 4–6 hours of filtered or partial sunlight per day. Morning sun with afternoon shade is usually ideal, especially in hotter climates or during intense summer heat.
Too much direct afternoon sun can scorch the leaves and dry the plant out, while too much shade can reduce flowering and make the plant leggy. In areas like Connecticut and the Northeast, many rhododendrons perform very well under tall trees where they receive dappled light throughout the day.
A few signs to watch for: too much sun shows up as curled leaves, brown edges, and faded foliage, while too much shade shows up as fewer blooms, thin growth, and slower development. Keeping the soil consistently moist and mulched also helps rhododendrons handle sunnier conditions more successfully.