Homeowners favor lavender (Lavandula spp.) for its often silvery foliage, pink-to-blue flowers and unmistakable fragrance. Most common lavender species and cultivars grow best in U.S. Department of Agriculture plant hardiness zones 5 through 8, making them suitable for north Florida gardeners; French lavender (Lavandula stoechas) grows in USDA zones 8 and 9. English lavender (Lavandula angustifolia cvs.) will grow in zones 9 and 10, although it may be short-lived and succumb to summer's heat throughout all of Florida.
Lavandula isn't a particularly large genus; only a couple dozen species exist. The plants grow native in dry, sunny and rocky areas throughout the Mediterranean, India, Asia and Africa. Most are evergreen or semi-evergreen in the United States and boast a silvery, gray-green foliage. The spikelike flowers, which typically sit along tall stalks, come in pink, blue, lavender and everything in between. Some species and cultivars make excellent culinary ingredients, although most people grow them for the lavender fragrance.
When choosing a site, look for a full-sun location with well-drained soil. Rocky or sandy soil works well for lavender; clay soil often holds too much water for these dry-loving herbs. While much of northern Florida has sandy soils like the rest of the state, some areas have a highly clayey soil, which won't work well for lavender.
The soil should have a pH close to neutral; a pH of 6.5 to 7.5 is best for these aromatic plants.
English lavender's planting season in USDA zone 8 is year-round. Transplanting lavender plants in spring is ideal; however, fall planting works well if the plants get at least two months of nice weather to establish before northern Florida's mild winters set in.
Space plants 1 1/2 to 2 feet apart; dig the planting holes as deep as the root ball and at least 1 1/2 times as wide.
Although you can sow seeds in a cold frame, most gardeners choose to either purchase young plants from nurseries or propagate from cuttings. Most varieties will not grow true when planted from seed.
For seed, sow 1/8-inch deep in a flat with soil-less planting media and lightly cover the seeds with perlite. Water the pots regularly to keep soil moist. Seeds germinate and grow slowly; germination typically takes two to three weeks. Use a heating pad to keep the temperature around 70 degrees.
To propagate by cutting, cut a strong stem below a leaf or bud node, remove most of the lower leaves, dip the stem in rooting hormone and plant the stem in warm, moist potting soil. Once the cutting takes root, transfer it to a growing pot or prepared outdoor bed.
Fertilizing and Watering
Once established, most varieties of lavender are low-maintenance, hardy plants that tolerate a wide array of climatic and soil conditions. You don't need to fertilize lavender; adding 1 inch of compost around the plant at planting time and once per year typically feeds the plant enough.
Even northern Florida experiences particularly hot summers, sometimes hotter than more southern parts of the state. In USDA zones 8 and higher, add 1 gallon of water each week until the lavender plant is established. Once mature, water with 1/2 gallon of water every two weeks or so up until bud development. For maximum flower productivity, water once or twice per week from flowering through harvest.