The fragrant, silvery foliage and vibrant purple blooms of lavender ( Lavandula spp.) make it a cherished garden plant, but its beauty can quickly become a challenge when the plant grows too large. Over time, overgrown plants often develop a large, unsightly structure with bare stems. Addressing a lavender plant that has become too big requires understanding its natural growth cycle and applying specific pruning techniques to restore a compact, bushy shape. This process involves both an immediate fix for severe overgrowth and a long-term, routine plan to maintain the desired size.
Why Lavender Becomes Woody and Leggy
Lavender is classified as a subshrub, meaning it develops a woody base, unlike herbaceous perennials that die back completely each year. This growth habit naturally causes the stems to harden and lose their ability to produce new leaves along the lower sections as the plant matures. When lavender is left unpruned for several seasons, the soft, green growth remains only at the tips of long, bare stalks, creating a sparse, “leggy” appearance and a significantly woody center.
This woodiness is a normal part of the plant’s aging process, but a lack of regular trimming accelerates it. The older, thicker stems at the base become rigid and do not readily sprout new growth, which is a major constraint in rejuvenation. Furthermore, the eventual size is determined by its cultivar; English lavenders (Lavandula angustifolia) and their hybrids (Lavandula x intermedia) can grow significantly larger than French or Spanish varieties. Pruning is a necessary practice to counteract this natural tendency and keep the plant vigorous and compact.
Reviving Severely Overgrown Lavender
For a lavender plant that has been neglected and is now significantly overgrown, rejuvenation pruning is the only way to manage its size. This aggressive cut is inherently risky because lavender generally does not regenerate from completely bare, old wood.
Timing and Technique
The best time for this severe pruning is in the early spring, just as new growth begins to emerge and after the risk of a hard frost has passed. Waiting for new leaves to sprout helps identify the plant’s current living tissue. The technique involves cutting back the overgrown stems by a substantial amount, sometimes up to two-thirds of the plant’s height, but crucially, never cut into wood that shows no signs of life. The goal is to locate the lowest point on the stem that still exhibits a few leaves or a small, green bud node and make the cut just above that point. If you cut into the completely bare, gray, or brown wood where no green tissue or small nodes are visible, that particular stem may not regrow, potentially leaving a permanent hole in the plant.
Gradual Rejuvenation
If the plant is exceptionally woody, it is safer to perform this rejuvenation gradually over two to three seasons, cutting back only a portion of the old wood each year. This staged approach minimizes shock to the plant and increases the chance of successful regrowth from dormant buds near the base. Though this method carries a risk of failure, especially with hybrid varieties like Lavandula x intermedia, it offers the best chance to restore a dense, manageable shape to a deeply neglected plant.
Maintaining Size with Annual Pruning
Once an overgrown plant has been rejuvenated, or if you are managing a healthy plant, annual pruning is the preventative measure against future excessive size. This routine trimming is much less severe than rejuvenation and focuses on removing the soft, green growth to maintain a dense, mounded shape. The most effective time for this maintenance cut is immediately after the main flowering period has finished in late summer or early fall.
The general rule is to remove approximately one-third of the plant’s current green foliage, or to cut down to the top two sets of leaves on each stem. This cut should consistently stay well above the old, woody base of the plant, ensuring you only remove the current season’s growth. Performing this trim in late summer allows the plant enough time to develop new growth before the onset of winter, which helps protect the plant from cold damage.
A secondary, lighter trim can be performed in the early spring to remove any dead or winter-damaged tips and to shape the plant before the new season’s growth begins. By consistently removing the soft, flexible stems each year, you stimulate lower branching and prevent the stems from hardening into bare wood, ensuring the plant remains a compact, productive size.