Gardening

My lavender is brown and sad looking after winter frost. Can I revive it?

Will my plants come back or should I cut my losses?

Fast-growing and fragrant, lavender is the most quintessential of summer flowers. Photograph: iStock

Fionnuala Fallon
Sat Apr 6 2024 - 05:00

I put down a lavender border last summer on my driveway. Unfortunately, it looks like the winter frost damaged some of the plants. They are quite brown and sad looking compared with the others. Will they come back or should I cut my losses? GL, Co Kildare

Fast-growing and fragrant, lavender is the most quintessential of summer flowers, conjuring up images of scented lavender fields and garden picnics. But the problem is that this sun-loving, evergreen, naturally rather short-lived, shrubby perennial really isn’t a fan of our cool, damp Irish climate, especially if it’s unfortunate enough to be planted into shade and/or any kind of soil that’s less than free-draining. Climate change has made things even more challenging, resulting in summer deluges and winter waterlogging of soils. Rather than cold weather, it’s the latter in particular that spells death for lavender.

As regards your sad-looking, probably-dead lavender plants, you could try digging them up and transplanting them temporarily elsewhere in the garden or into pots on the chance that they might recover. But it will be a slow business and I think that on balance it’s not worth it. So my suggestion is to bin them and then take a close look at the growing conditions to see if these need to be improved.

If your lavender hedge is planted in shade, then unfortunately you’ll need to relocate it elsewhere. Even if it’s growing in full sun, is the soil heavy, wet, and/or compacted and inclined to winter waterlogging? If so, you’ll need to improve it integrating plenty of coarse horticultural grit and even some fine pebble. Another alternative is to create a slightly raised bed by gently mounding up the soil. As little as 15cm can make all the difference to the plants’ root systems, preventing them from rotting in cold, wet ground in winter.

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To do this and prevent any further losses, start by temporarily lifting the remaining plants (do this as soon as possible, making sure to preserve as much of each root-ball as you can). Then place them tightly together on a sheet of plastic or cardboard to stop their vulnerable roots from drying out while you quickly improve the soil as suggested above. Then replant each plant to its original planting depth before finishing off with a generous watering to help their roots to quickly re-establish. For a lavender hedge, plants should be spaced 30cm apart.

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Bear in mind also that several different species of lavender are widely sold in garden centres, with different levels of hardiness. Varieties of English lavender (Lavandula angustifolia) and the hybrid species Lavandula x intermedia are best suited to growing in an Irish garden while varieties of French lavender (Lavandula stoechas) and Spanish lavender (Lavandula latifolia, Lavandula pedunculata and Lavandula viridis) are much less tolerant of cold and wet and should be treated as half-hardy perennials.

Also bear in mind that to replace your missing plants with exactly the same variety may prove challenging. One good, affordable solution is to propagate them from softwood or semi-hardwood cuttings taken in summer. Finally, bear in mind that a lavender hedge needs careful annual pruning, starting with a light clipping in spring to remove untidy or frost-damaged growth and then a light trim in late summer after flowering to remove spent flowers and no more than 2cm-3cm of the top layer of foliage.

Fionnuala Fallon

Fionnuala Fallon

Fionnuala Fallon is an Irish Times contributor specialising in gardening

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