Lavender, with its purple spikes and calming fragrance, is a cherished feature in UK gardens. This Mediterranean native requires routine attention to maintain its compact shape, maximize blooms, and prevent it from becoming a leggy, woody shrub. Pruning is the annual practice that ensures the plant’s health, encourages a dense habit, and guarantees a spectacular display of flowers.
Timing Your Pruning: The Annual Calendar for UK Lavender
The best time to prune lavender in the UK depends on the specific variety, primarily distinguishing between the popular English and the more tender French types. English lavender (Lavandula angustifolia) is the most common and benefits from a two-stage pruning schedule. The main cut should happen immediately after the first flush of flowers fades (late August to early September), allowing the plant time to recover and harden new growth before the first frosts.
A second, lighter trim can be carried out in early spring (March or April) as new growth emerges. This spring trim focuses on removing any dead, weak, or winter-damaged stems to tidy the plant before the main growing season. This two-stage approach prevents the plant from becoming woody and ensures a tight, productive form for the summer.
French and Spanish lavenders (Lavandula stoechas or Lavandula dentata) are less hardy and have a longer flowering season. These varieties require continuous deadheading throughout the summer to encourage repeat flowering. A light, shaping trim should be given right after the main flush of flowers, but never later than mid-September to avoid frost damage to vulnerable new shoots. Due to their borderline hardiness, major cuts should be avoided entirely, focusing only on removing spent flowers and maintaining a tidy shape.
Mastering the Technique: How to Cut Back Lavender
Routine annual pruning requires only clean, sharp secateurs or shears. The goal is to remove spent flower stems and approximately one-third of the current season’s green growth. Follow the flowered stem down and make the cut just above a set of new leaves, known as a leaf node.
Pruning above a leaf node ensures the cut is made into soft, green growth, stimulating the plant to produce new shoots. This encourages a dense, bushy structure, preventing the plant from becoming leggy and sparse. When pruning, aim to shape the shrub into a slightly rounded mound, which promotes air circulation and allows light to reach the lower parts of the plant.
The most important rule is to never cut into the old, gray, woody part of the stem. Lavender is a semi-woody shrub that does not readily regenerate from old wood; cutting into it can create bare patches or kill the branch. Always ensure a few inches of healthy green foliage remains above the woody base to facilitate successful regrowth.
Dealing with Neglect: Hard Pruning for Rejuvenation
For older, neglected lavender that has become woody, sparse, and leggy, hard pruning may be the only option for revival. This high-risk technique is a last resort, as there is no guarantee the plant will recover, especially for varieties other than English lavender (L. angustifolia). The correct time for this measure is in early spring, typically late March or April, just before new growth begins.
Pruning in early spring gives the plant the longest possible recovery period before winter. The method involves cutting back a portion of the woody stems, but only if small, green shoots or buds are emerging lower down the stem. If the plant is very old, it is safer to attempt rejuvenation gradually, cutting back only about one-third of the woody stems each year over two to three years.
A more radical approach is to cut the entire plant back to about six inches, but this should only be attempted if there is evidence of low-down green growth. If the stems are completely bare, gray, and brittle, cutting into them will almost certainly prevent any regrowth, potentially resulting in the loss of the plant. Hard pruning forces the plant’s energy into producing new basal growth, but the risk of failure remains high.