The best times to cut back lavender are in the late summer and early spring. Early spring is a great time to cut back dead wood to healthy growth and to shape the base of the plant before it puts on flower stalks. Flower stalks are commonly harvested in the summertime, and the entire plant can be lightly cut back by about 1/3 of the total stem length and shaped into a neat mound in late summer or early autumn.
When to cut back lavender
The best times to cut back lavender plants are in the early spring or late summer. If pruning in early spring, wait until the plants come out of winter dormancy by looking for new growth before pruning. Also, take note of any parts of the plant that were damaged or died during the winter and trim those out of the plant to make room for fresh stems.
Lavender plants are sometimes cut back in the summertime to harvest the fresh flower stalks for arrangements or to dry for crafts or other scented purposes. This is especially true for English lavender and lavandin, as they are most commonly used for these applications. Spanish lavender is sometimes used in fresh arrangements, while French lavender is usually only used as a landscaping plant and is left to flower on the plant.
For all types of lavender grown as landscaping plants in the garden, the flowers are generally left on the small shrubs until they fade in late summer. The spent flowers can then be removed in late summer, including the stalks. You can also cut back lavender growing in pots and lavender trees in the late summer after they flower.
Deadhead the plant by snipping off the spent flowers, including their stem, down to the leaves. Then give the plant a light trim overall to shape it into a rounded mound. Remove about 1/3 of the length of each stem. This keeps the plant looking neat and shapely and also feeds the desire of many gardeners to get their yards ready for winter.
Here are some expert tips about when to cut back lavender:
“Lavendula: Maintenance includes an annual barbering just after new growth has appeared: cut back by a third to encourage compact, vigorous growth. Beware of pruning too early, as soft young growth may get frosted.”
Essential Perennials: The Complete Reference to 2700 Perennials for the Home Garden, by Ruth Rogers Clausen and Thomas Christopher
“Lavandula angustifolia (Common or English Lavender): Prune in spring to keep the plant neat to remove winterkilled wood. Later in the growing season, clip off spent flower heads as they form.”
The Pruning Book: Completely Revised and Updated, by Lee Reich
How to cut back lavender
Start your spring lavender pruning by removing any dead wood or damaged or diseased branches. Then cut back the plant by removing 1/3 of the length of each branch. Try to leave 2/3 of the length of each live branch on the plant. Cutting back lavender is easiest with a pair of handheld pruning shears.
Why lavender is cut back annually
Lavender should be cut back in the spring mainly to remove any branches that were damaged or died during harsh winter conditions. Trimming the shrub keeps the plant neat, as well as encourages the plant to grow more vigorously (and in a more compact form).