When people refer to a “lavender tree,” they usually mean a large, mature lavender shrub with a woody base or a plant trained into a standard form with a single trunk and a rounded canopy. Regular pruning is the most effective practice for maintaining the plant’s characteristic mounded shape and preventing it from becoming leggy or sparse. This maintenance promotes health by increasing air circulation and maximizes the production of fragrant, oil-rich flowering spikes. A proper pruning strategy extends the productive life of the plant, ensuring a dense, attractive canopy.
Essential Preparation and Timing
Before making any cuts, ensure your tools are clean and sharp to guarantee precise cuts that heal quickly. Bypass pruners are the preferred tool for clean snips on individual stems, while sharp hedge shears may be used for rapid shaping of the canopy. Sanitizing the blades with rubbing alcohol or a bleach solution before and after use prevents the transmission of plant pathogens.
Lavender benefits from two distinct pruning periods, which vary depending on local climate and species. The first, lighter trim should occur immediately after the initial flush of flowers fades, combining deadheading with a light shaping cut. The main shaping cut should be performed when the plant is not under stress, typically in late summer or early fall after the final bloom has finished. In regions with harsh winters, many gardeners delay the primary cut until early spring, just as new growth begins, to avoid exposing fresh cuts to freezing temperatures.
Step-by-Step Guide to Annual Shaping
The rule for routine annual pruning is the “one-third rule”: never remove more than one-third of the plant’s green, leafy growth in a single season. This restraint ensures the plant retains sufficient foliage for photosynthesis while stimulating a dense, branching habit. Severe cutting into green growth can stress the plant. The goal is to cut back the faded flower stems and the top portion of the green growth to maintain a compact, rounded form.
Each cut should be made precisely above a leaf node, the small bump where new growth or leaves emerge from the stem. Cutting just above this node redirects the plant’s energy, leading to bushier growth beneath the cut. Focus on the pale green, softer growth and avoid cutting into the darker, grayish, woody material during routine maintenance.
To preserve the desirable “tree” shape, maintain a slightly rounded dome. This shape allows sunlight to penetrate the center and promotes air circulation. Shaping the plant this way prevents stems from flopping outward and developing a hollow or sparse center. Consistently removing the top third of the stems encourages lateral branching, keeping the canopy dense and ensuring a prolific display of flowers the following season.
Annual shaping controls the plant’s growth habit and prevents excessive woodiness, rather than reducing its size dramatically. Consistent, moderate removal of soft growth ensures the plant remains vigorous and productive. Small, frequent cuts are less stressful than infrequent, severe reductions.
Rejuvenating Overgrown or Woody Plants
Neglected, woody lavender plants require a different approach than routine shaping. Lavender rarely sprouts new foliage from the old, gray, leafless wood, often called the “dead zone.” Cutting into this old growth will likely result in a permanent, unsightly stub with no new shoots developing.
If rejuvenation is necessary for an overgrown plant, use a gradual, multi-year approach. Start by cutting back only one-third of the oldest, woodiest stems to just above the lowest visible signs of green growth, even if it is only a tiny bud near the base. Time this reduction for early spring, allowing the plant the entire growing season to recover. The remaining two-thirds must be left intact to sustain the plant through photosynthesis and encourage low buds to break dormancy.