I installed landscape lighting when we were remodeling our garden. All light bulbs are 7 watts. The three lights are spots that illuminate small trees, 2 dwarf citrus and 1 Chinese style. 7 watt bulbs are too weak. 11-watt bulbs add a bit more light, and believe it or not, the extra wattage makes a difference. You don't have to change the entire system to emphasize specific areas, just change the strength. Make sure you have a transformer that can handle the extra load (power).