Lavender is a fragrant, hardy perennial shrub prized for its silvery-green foliage and iconic purple flowers. Unlike soft herbaceous plants, lavender develops a woody base over time, requiring consistent pruning for continued health. Regular trimming prevents the plant from becoming woody, sprawling, and hollow in the center, a common issue known as “legginess.” Pruning encourages new, soft growth that produces abundant flowers, maintains a compact shape, and prolongs the plant’s productive lifespan.
The Two Primary Pruning Windows
The most substantial pruning session should occur just after the main flowering period, typically in late summer or early fall. This timing allows the plant to redirect energy from seed production into developing a strong, bushy mound of new foliage. Removing spent flower spikes and a portion of leafy stems ensures the plant establishes a dense, protective base before winter.
It is important to complete this heavy cut at least six to eight weeks before your region’s first expected hard frost. Pruning too late stimulates tender new growth that lacks time to harden off, making it vulnerable to cold damage. For many varieties of English lavender, this window often falls between late August and mid-September.
A secondary, lighter pruning is beneficial in early spring, just as the first signs of new growth appear. This is a tidy-up to remove any dead, damaged, or brittle stems resulting from winter weather. Waiting until new leaves sprout helps identify where the living tissue begins, ensuring you do not cut too deep into the plant’s dormant wood. This spring trim also refines the overall shape before the season’s new growth begins.
Essential Pruning Techniques
When performing the main late-summer prune, aim to remove about one-third of the plant’s total green growth. This technique, sometimes called the “Rule of Thirds,” encourages vigorous branching without stressing the plant severely. Focus cuts on the leafy, non-woody stems, trimming them back to just above a set of leaves or a small, visible new shoot.
The fundamental rule of lavender pruning is to avoid cutting into the “old wood,” which is the brown, leafless, hardened central structure of the plant. Unlike many other shrubs, lavender rarely produces new growth from this old wood. Cutting into this section can create a permanent bare patch or lead to the death of the entire plant.
The goal of annual pruning is to maintain a rounded, dome-like shape that is slightly narrower at the top. This shape promotes excellent air circulation, which helps prevent fungal diseases and encourages uniform growth. Sharp hand pruners are ideal for making clean, precise cuts on individual stems, while hedge shears can be used for quickly shaping large, established rows.
Rejuvenating Overgrown Plants
When a lavender plant has been neglected for several years, it often becomes a woody, sprawling mass with only green foliage at the tips. Attempting to restore such a plant is a high-risk endeavor, as cutting into the old, brown wood may kill it. Before attempting rejuvenation, assess the plant for any tiny, new green shoots emerging from the lower, woody stems, as their presence indicates a chance of success.
The recommended method for an overgrown plant is a gradual renovation, spreading the hard cuts over two to three growing seasons. In early spring, remove one-third of the oldest, woodiest stems, cutting them back to within a few inches of the ground or to the nearest visible sign of new growth. The remaining two-thirds of the plant is left intact to sustain it through the season.
The following year, repeat this process on the next third of the old wood, slowly forcing the plant’s energy into new growth from the base. This cautious, phased approach minimizes shock and increases the odds of survival. The success rate for reviving severely woody lavender is notably lower than with regular maintenance. If no green growth appears after a season of rejuvenation efforts, the plant may be beyond saving and should be replaced.