Lavender's grey or light-colored foliage reflects sunlight. In hot and dry conditions, this reflective quality prevents the plant from absorbing excess heat. By reducing the heat absorbed by the plant and inhibiting water loss, the foliage acts as an air conditioner.
Small leaves assist the lavender plant in surviving drought as the reduced surface area of the foliage reduces the plant's intake of water. Lavender can survive days without water. In fact, drought conditions aid in producing the ornamental and culinary qualities desired in lavender. These include the aromatic nature of the flowers and the spectacular silver color of the leaves.
The leaves of the lavender plant are covered with fine, silver hairs. These hairs improve lavender's drought resistance by locking in moisture and reducing the amount of transpiration that occurs. Additionally, the fine hairs lower the temperature inside the leaf and provide a shield from drying winds.