Lavender is a Mediterranean plant. Regular pruning is necessary for this semi-woody shrub to ensure robust flowering and maintain a dense, compact shape. Without consistent annual trimming, lavender plants quickly become leggy and woody, resulting in sparse blooms and a short lifespan. The timing and technique of these cuts are important in NorCal, where the long growing season influences the plant’s growth cycle. Understanding the specific calendar for pruning will ensure your lavender remains vigorous and productive year after year.
The NorCal Pruning Calendar: Timing Seasonal Cuts
Successful lavender maintenance in Northern California involves two distinct pruning periods, each with a different goal. The first is a light trim, or deadheading, performed right after the main flush of flowers fades, typically in late spring or early summer (June or July). Removing these spent blossoms prevents seed production, redirecting energy into new vegetative growth and often encouraging a second, smaller bloom.
The second, more significant pruning, often called a hard prune, is performed when the plant is dormant. In the mild microclimates of Northern California, the optimal time for this major structural cut is typically late winter, specifically late February or early March. This timing is designed to shape the plant while it is not actively growing, but before new seasonal buds begin to swell. Pruning at this time allows the plant to use the first burst of spring energy to produce a dense canopy of new growth.
Delaying the hard prune too late into spring can reduce the number of blossoms for the coming year, as you risk removing developing flower buds. Conversely, pruning late in the fall is discouraged because it can stimulate tender new growth that lacks the necessary time to harden off before any unexpected cold snaps. Performing the substantial cut in late winter takes advantage of the mild dormancy period to prepare the plant for vigorous summer growth.
Essential Techniques for Long-Term Lavender Health
For established plants, aim to remove between one-third and two-thirds of the soft, green, leafy growth from the past year. The goal is to leave several inches of green foliage intact above the woody base, which serves as the engine for the next year’s growth. This annual reduction helps prevent the plant from becoming excessively woody and sprawling.
When performing the light post-bloom trim, snip off the spent flower stalks just above the first set of leaves on the stem. This tidying cut can be done with sharp hand pruners or hedge shears. For the hard prune, always use sharp, clean bypass shears to ensure a smooth cut that minimizes damage to the stem tissue. A clean cut heals faster and reduces the risk of disease or pest entry.
Shaping the plant into a rounded or dome-like silhouette is an important part of the hard prune. This shape ensures that sunlight reaches all parts of the shrub, promoting dense foliage from the base to the tips. Cutting the outer stems slightly shorter than the central ones helps achieve this compact, rounded structure.
Avoiding Damage: Understanding Woody Growth
The most important rule in lavender pruning is to never cut into the bare, leafless, old wood. Lavender is classified as a semi-woody shrub, meaning older stems gradually lignify and turn brown, forming a woody structure. Unlike many true shrubs, lavender does not reliably produce new shoots from this hardened wood. Cutting deeply into the woody base can create a wound that the plant cannot heal, often leading to the death of the entire stem or the whole plant.
If you examine an older lavender plant, the woody growth will appear gray or brown, lacking the silvery-green leaves present on younger stems. Consistent annual pruning is designed to prevent this woody growth from extending too far up the plant, keeping it confined to the base. If a plant has been neglected for several years and is extremely woody, perform a light prune, leaving a cushion of green leaves. Regularly removing only the soft, green material ensures the plant remains vigorous without risking the structural damage associated with cutting into old wood.