My lavender hedge is looking very overgrown and more than a bit sorry for itself. I know I should have pruned it last summer but never got around to it. Can I do it at this time of year, or has that ship sailed?
M. Hartigan, Co Waterford
Native to the Mediterranean, this highly ornamental, semi-evergreen woody subshrub is prized for its intensely fragrant, silver-grey foliage and its mass display of perfumed, typically purple-blue flowers in summer. But our cool, damp Irish climate can be unkind to it, especially if the plants aren’t given a very free-draining spot in full sun, in which case they can become weak, leggy and even diseased.
On top of that, lavender plants really benefit from a gentle annual trim immediately after flowering to keep them in shape and encourage them to make plenty of sturdy, healthy new growth on which to flower the following summer. Without this annual haircut, plants soon start to sprawl, while the woody stems often start to split at the base, and the display of flowers falters.
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The reason for pruning immediately after flowering is that it produces new growth well in advance of the first harsh frosts of autumn, allowing those new shoots enough time to toughen up and withstand winter without damage. But if you didn’t get round to doing it in late summer, you can still lightly clip your lavender plants in late March/April to just above any newly emerging shoots, removing any faded flowers or frost-damaged stems. Just make sure not to cut back hard into any old wood (lavender plants typically won’t reshoot from old wood) and to use a very sharp, clean shears or secateurs.
Bear in mind also that lavender plants are naturally short-lived, even with careful annual pruning. If yours are already several years old and very leggy or woody with few new shoots near the base, then it may be best to bite the bullet and replace them. Mid-spring is the best time to do this. Ideally, choose a cultivar of English lavender (Lavandula angustifolia) rather than the less hardy French lavender (Lavandula stoechas) or the hybrid species known as Lavandula x intermedia. Recommended varieties include Lavandula ‘Hidcote’, Lavandula ‘Munstead’ and Lavandula ‘Melissa Lilac’.
