There are so many types of lavender, and with that different types of purning. If you know what kind of lavender plant you have it will make it easier.
However a general homeowner plant should be pruned twice. Start in the spring in late May or early June before any buds show on your plants. With a pair of sharp clippers, trim the tops of the plant that are soft leaves only. You do not want to cut into the woody part of the plant. Shape your lavender plant like a round soccer ball if you can.
The second time to trim your lavender and the most important time is in the late summer, end of August. Trim off all the flowering stems. This will protect your lavender plant over the winter and put energy into the roots for regrowth the following year.
Emily Rozema: Owner, Grower, Entrepreneur