Pruning lavender so it does not go woody: two cuts a year

Lavender is the essence of summer: violet mounds that scent the midday heat and hum with bumblebees. And yet many fail because their lavender falls apart after a few years, grey and bald below, a few sparse shoots on top. The reason is almost always the same, and it is easy to fix: the missing or wrong cut. Master that, and you have a dense, long-lived lavender that flowers more lavishly year after year.

The cut is everything

Lavender is a subshrub that goes woody from below. From this old, leafless wood it re-sprouts only very reluctantly. So if you never cut, or always too timidly, the bush grows up and away, gets top-heavy and breaks apart over the years. The solution is two firm cuts a year that keep forcing it back into a compact dome.

1. Spring cut: the shaping cut

   In early spring, roughly CW 12 to 16, cut the whole bush back by about a third to a half and shape it into a round dome. This is the more important of the two cuts, it sets the form for the whole year.

2. Always stay above the green

   When making the spring cut, make sure to leave a hand's width of green shoots everywhere. Better to cut a little less deep than to stray into the bare wood by accident.

3. Summer cut: after flowering

   Once the flowers have faded in July or August, cut out the spent stems along with a small piece of green. That keeps the bush tidy and encourages a second, smaller flush.

4. Cut nothing in late autumn

   Skip a hard cut just before winter. The soft new growth would freeze unprotected. Anyone who cuts in autumn risks the plant.

Spot and soil: sun, chalk, drainage

Lavender is one of the Mediterranean herbs and wants exactly what thyme and sage like: the hottest, sunniest spot in the garden and a free-draining, rather lean, chalky soil. Waterlogging is deadly, especially in winter. On heavy loam, work in plenty of sand and fine gravel before planting, or plant on a small mound.

Lavender needs hardly any feeding. Too much nitrogen makes it soft, lush and less hardy. Lean is better than rich.

Planting

Best set lavender in spring, once no hard frost is coming, from about CW 16. That way it has the whole summer to root before the first winter. For a small hedge or edging, plan 30 to 40 cm spacing. Water fresh plantings regularly in the first summer, after that established lavender manages almost without extra water.

Propagating is easy from cuttings: half-ripe, non-flowering shoots taken in summer and stuck into sandy substrate root reliably.

Bloom, bees and harvest

The violet flower spikes appear from June to August depending on the variety and are one of the best bee pastures there is. If you want to dry lavender, harvest it when the lower flowers of the spike have just opened, on a dry morning. Then tie the stems and hang them upside down in an airy, shady place. That keeps the most colour and scent.

Varieties: which lavender for which purpose

Overwintering

Common lavender is hardy enough here and survives frosts down to about minus 15 degrees. More important than any protection is, again, drainage: the most common cause of losses is not cold but wet feet in winter. In harsh spots and during bare frost, some brushwood over the base helps. In a pot the root ball is frost-prone, so stand the container by the house wall and pack it in fleece. French lavender overwinters best frost-free, bright and cool indoors.

Using it

Dried lavender scents for months and, in little sachets, keeps moths out of the wardrobe. In the kitchen use common lavender very sparingly; a few flowers scent sugar, biscuits or a herb salt, too much quickly tastes soapy. The flowers are also a pretty, edible scatter over desserts.

Enter the two pruning dates as recurring tasks in your garden journal, the shaping cut in spring and the cut back after flowering. With these two dates the same lavender accompanies you for many summers, dense and fragrant instead of bald and aged.

Common questions about lavender

When and how do I prune lavender correctly?

Twice a year: in spring, roughly CW 12 to 16, a firm shaping cut by a third to a half into the round dome shape, and after flowering in summer a lighter cut back of the spent stems. Always cut only into the green leaf, never into the bare wood.

My lavender is woody and bald at the bottom, what can I do?

Lavender barely re-sprouts from old wood, so a badly gone-bald bush is rarely fully saveable. Try a careful cut back to just above the lowest green shoots, it often re-sprouts there. To be safe, raise a successor from cuttings at the same time.

Which lavender is hardy?

Common lavender Lavandula angustifolia is the hardiest here and survives about minus 15 degrees. French lavender, by contrast, is not hardy and is best overwintered frost-free.

Why does my lavender not flower properly?

Usually it lacks sun, the soil is too wet or too rich, or the cut is missing. Lavender needs the hottest, most free-draining spot, little water, hardly any feed and the yearly shaping cut to stay dense and free-flowering.

Can I keep lavender in a pot?

Yes, well even, as long as the spot is full sun and the container has a drainage hole. Use free-draining, sandy soil, water sparingly and stand the pot sheltered by the house wall with a fleece jacket in winter.