Lavender is one of those plants that a great many Irish gardeners are quietly killing with good intentions. The impulse, when a lavender bush starts looking straggly and woody and overgrown, is to cut it back hard and start again. It seems logical. The plant looks like it needs a reset. The problem is that lavender does not work that way. Cut it back into the old wood and it will not regenerate from those stems. It will simply sit there, looking increasingly bare, and in most cases it will die. The hard prune that seemed like the solution is the thing that finished it. Understanding this one fact about lavender changes everything about how you manage it.

The approach that keeps lavender healthy, bushy and flowering well for many years is the opposite of the hard prune. It is regular, gentle trimming throughout the growing season, starting early and repeated at the right points through the year. The goal at every stage is the same: keep the plant compact, prevent it from getting away from you, and never allow it to put so much energy into woody growth that the green productive stems are left sitting on top of a dead brown base with nothing below them to cut back to. If you do that consistently from the beginning, lavender is a remarkably easy and long-lived plant. If you let it get ahead of you and then try to correct it with a hard cut, you are very likely to lose it.

In terms of timing, there are three moments in the Irish gardening year that matter for lavender. The first is early spring, March into April, before the plant breaks into its first flowering. At this point give the whole plant a gentle trim, taking off the top inch or two of growth and tidying the overall shape. You are not removing much material at this stage. You are encouraging the plant to put its energy into a compact, bushy structure rather than long, loose stems, and you are removing any growth that has been damaged or browned over winter. This is a light, shaping trim rather than any kind of serious cut. Done consistently each year it makes a significant difference to how the plant develops over time.

The second moment is after the first flowering, which in Ireland typically falls in June and into July depending on the variety and the season. Once the flower stems have gone over, cut them back and take another inch or so of the green foliage below. Again, you are working within the green growth only. The stems should have visible green leaves on them above where you are cutting. If you are looking at brown, woody stems with no green on them, you have gone too far. This post-flowering trim tidies the plant, stops it putting energy into setting seed, and often encourages a second flush of flowers. In a decent Irish summer, many lavender plants will give a second flowering in August and into September, and this is particularly worth encouraging because it extends the season and keeps the plant looking good through the later months.

The third trim comes after that second flowering, in September. This is the most cautious of the three. You are removing the spent flower stems and the top of the foliage only, no more than an inch off the green growth. Never cut lavender hard in September. The plant is moving towards its dormant period and does not have the growing season ahead of it to recover from anything more than the lightest touch. Take off what has flowered and finished, tidy the shape lightly, and leave it. That is all it needs at this point. Going any deeper in autumn is how gardeners lose lavender plants over winter, leaving fresh cut surfaces exposed to the wet and cold of an Irish autumn with no time to harden before temperatures drop. If you think of how vulnerable fresh new growth is to cold and wet, the same principle applies in reverse to fresh cuts made late in the season.

What this three-stage programme gives you is a lavender plant that never gets the chance to become woody and unmanageable, because you are addressing that tendency at every stage before it takes hold. The gardener who inherits an already woody, neglected lavender is in a more difficult position. If there is still green growth visible within a few inches of the woody base, there is some hope — a very careful trim back towards that green, over two seasons rather than one, may stimulate new growth from lower down. But it is a rescue attempt rather than a reliable fix, and it does not always work. If the plant is entirely woody with no green showing below the scraggly top growth, it is almost certainly beyond saving and replacement is the honest answer. Propagating from cuttings taken from any green growth that remains, or from a healthy plant elsewhere, is a practical way to replace it with something that already carries a little history.

Lavender's other requirement in Irish conditions is worth mentioning because it connects directly to how well it responds to trimming. It is a Mediterranean plant and it insists on free-draining soil. In our wet climate, lavender sitting in heavy, moisture-retentive ground through a wet Irish winter will struggle regardless of how well you prune it. Improving drainage in the soil around lavender with grit and a biochar-enriched compost makes a significant difference to how the plant performs and how resilient it is to the trimming programme described above. Good drainage is not just a preference for lavender. In Irish conditions, it is a prerequisite for the plant surviving at all. If your lavender has been struggling and you are not sure whether the issue is pruning, soil or both, tell me about your garden and I can advise on the most likely cause and the best next steps for your specific situation.