Clean Your lavender up.... Once your lavender plant has had one year to establish itself, you will need to prune your lavender once a year. The best time to prune lavender is in the spring...prune off 1/3 of the plant. This will force the lavender to create new and more growth, which will not only keep the lavender bush from going woody, but will also help to increase the amount of lavender available for harvest later in the season. gardengatenotes.com
