Lavender (Lavandula angustifolia) is a perennial herb native to the hot and dry areas of the Mediterranean. Gardeners prize its light purple blooms for fragrances, dried flowers and crafts, and they are a favorite of butterflies. This drought and heat tolerant shrub will grow in USDA Plant Hardiness Zone 9. The University of Florida Extension website warns that lavender may struggle in areas south of Zone 8, due to intense summer heat and humidity.
Choose a site that receives full sun. Lavender requires at least six to eight hours of direct sunlight to thrive. In the very southernmost parts of Zone 9, consider planting your lavender in an area that gets direct sunlight in the morning, and partial shade in the afternoon.
Amend your soil only minimally. Lavender prefers a somewhat infertile soil with an alkaline pH (above 6.0). Crushed oyster shells will increase soil drainage and also "sweeten" the soil, according to The Herb Companion.
Water your lavender only when the soil is dry. Constantly wet soil will lead to root rot. Fertilize with a balanced formula only if your plant is not thriving.
Deadhead your lavender to prolong blooming. Prune your lavender plant when you harvest its flowers or just after the plant has finished blooming.