The best time to plant lavender is in the spring between April and May. During this time, the soil is beginning to warm, which is needed for lavender to bloom. The herb grows best facing the south or west with full sun.
Lavender does not last long when it is planted in clay or other heavy soils. It grows best when planted in gravel and organic matter that offers plenty of drainage. Lavender does best in warm climates with as much sunlight as possible. Any locations within the USDA Zone 5 can grow lavender, as they have proper weather and climate conditions. An overly humid summer or severe winter kills lavender.