If the alluring aroma of French lavender, also known as Lavandula dentata, is not enough to sway your decision to cultivate this plant, you should also take into account the fact that it is resistant to deer and drought and requires very little care. French lavender, which has a paler hue than English lavender, lends itself particularly well to drying for use in the making of crafts and food. In the plant hardiness zones 8 through 11 of the United States Department of Agriculture, where several forms of French lavender spend most of the year in bloom, the environment is ideal for growing this variety of lavender.
Soil and Water
Growing lavender well requires a lot of light and soil that drains properly. Once they are established, the plants can survive in dry circumstances, but they cannot survive in soil that is always damp. Loose, sandy soil is excellent. You may plant lavender on raised mounds and amend the clay soil with organic matter, or you can plant it on raised mounds and dig lots of coarse material into the mounds to increase drainage. Lavender favours a neutral or slightly alkaline pH.
Getting Plants in the Ground
Planting French lavender on a mound allows for better drainage of any extra water that may accumulate. After the final frost of the spring, set your plants outside, leaving between 15 and 18 inches of space between each one. Plant seeds in the late winter or early spring, when there is still a chance of a light frost. Maintain a mild moistness in the soil, and be patient. It might take anything from two months to three months for the seeds of French lavender to germinate. Before applying mulch, you should wait until the seedlings have reached a height of between 5 and 6 inches.
In the event that there is no rain, the plants should be watered once every week during the first summer and then once every three weeks throughout following seasons. When the soil is maintained dry, the plants are able to develop to their full potential and provide the most fragrant scent. The use of gravel as a mulch around lavender plants not only gives the garden a more natural appearance but also helps prevent the soil from being too wet. Organic mulch retains moisture close to the plant at the soil line, which may promote the development of rot. Even though French lavender does not need yearly fertilising, the plants grow well with a thin covering of compost applied once every other year in the late autumn or winter.
Pruning for Health and Reblooming
If it seems as if the mature French lavender plants are not getting off to a good start, prune them back by one-third to one-half of their size. Remove any winter damage and do some mild pruning to form the plants into the desired shape if they begin to develop early in the spring. It is a good idea to prune the plants by one-third once every two or three years, regardless of whether or not the plants seem to need this action. During the summer, the only pruning that has to be done is the removal of dead flower stems, which may be lopped off all at once after a large flush of blossoms in order to stimulate further flowering. You may trim the dried flower stalks in the autumn if you don’t like how they appear, but you should be cautious not to cut into the section of the stems that still has leaves on it. When you prune a plant in the autumn and cut it back too much, it will stimulate new growth at a time when it should be saving its resources for the winter.
Before you prune the lavender or afterward, sterilise your pruning shears with rubbing alcohol or alcohol wipes to prevent the transmission of plant diseases or pests across your garden. You may do this either before you prune the lavender or afterward.