Lavender is valued for its distinctive fragrance, drought tolerance, and attractive mounding shape. Regular pruning is necessary to ensure the plant remains bushy, healthy, and produces abundant blooms. Without annual trimming, the plant will become leggy, flop open, and develop a woody base that produces fewer flowers.
Determining If March is Right for Pruning
The timing for pruning lavender in March depends entirely on your local climate and the last expected hard frost. Pruning stimulates new, tender green shoots that are highly susceptible to cold damage. If a hard frost occurs after pruning, it can severely injure or kill this new growth.
In colder climates (USDA Zones 6 and below), March is typically too early for the main spring pruning. The risk of severe frost often remains until late April or May. It is advised to wait until approximately four weeks before the average last frost date to minimize this risk.
A more reliable indicator than the calendar is the plant itself, which signals when it is safe to prune. Look closely at the base of the stems for the emergence of small, bright green shoots. These visible signs confirm the plant has broken dormancy, making it safer to remove old material.
Warmer regions, particularly USDA Zones 8 and higher, may find that March is suitable for pruning. The milder temperatures mean the threat of frost has often passed by the beginning of the month. Always check your local forecast, but the appearance of new growth remains the most dependable signal for spring cleanup.
Essential Pruning Techniques
The method of cutting is crucial for the lavender plant’s shape. The two primary types of cuts are the light maintenance trim and the more aggressive rejuvenation cut. The light trim is an annual practice where you remove approximately one-third of the plant’s current year’s growth.
This maintenance cut reshapes the plant into a tidy mound, removes winter-damaged tips, and promotes dense, low growth. Aim to cut just above a set of leaves on the soft, greenish-grey part of the stem. This encourages new lateral branching from that point.
A harder rejuvenation cut is reserved only for older, neglected plants that have become excessively woody and sparse. Avoid cutting into the bare, brown, woody base, as lavender does not regenerate new growth from this old wood. Cutting here may create a permanent dead gap or kill the entire plant.
To perform a rejuvenation cut safely, locate the lowest point on the stem where new green or soft grey growth is still visible. Make your cut just above this point, ensuring you leave at least one to two inches of healthy growth above the woody base. Always use clean, sharp bypass pruners or shears to make clean cuts, minimizing stress and disease risk.
Annual Pruning Schedule for Maximum Health
Pruning should be viewed as an ongoing maintenance task throughout the year. After the spring cleanup, the next significant opportunity occurs in mid-to-late summer, immediately after the first flush of flowers has faded. This post-flowering trim involves deadheading the spent flower stalks and lightly shaping the plant by removing up to one-third of the new foliage.
This summer cut encourages a second, smaller bloom in some varieties, such as English lavender (Lavandula angustifolia), and maintains a compact shape for winter. Delaying this cut forces the plant to expend energy on seed production instead of the new vegetative growth needed to prepare for the cold.
Pruning in late fall or winter is discouraged because the remaining foliage provides insulation and protection against cold damage. A late cut stimulates new growth that is easily killed by frost, leaving an open wound susceptible to rot and disease. If the late summer or early fall window is missed, it is safer to wait until the following spring.
Different lavender species have varied needs; English lavender is the hardiest and tolerates a more substantial, twice-a-year pruning. French and Spanish lavenders (L. stoechas and L. dentata) bloom earlier and more continuously, requiring lighter, more frequent deadheading after each cycle. Their less cold-tolerant nature means they should never be cut back hard in the fall.