When to plant lavender

April or May, never in winter

The RHS growing guide says lavender is best planted in April or May, as the soil naturally warms up.

It is just as clear about when not to plant. Lavender should never be planted in winter, the RHS says, when young plants are vulnerable to rotting in cold, wet soils.

After planting, water regularly. The RHS says newly planted lavender should be watered regularly during its first summer.

Which lavender to plant outdoors

The RHS says the hardiest lavenders are English lavender and its hybrids, cultivars of *Lavandula angustifolia* and *L. × intermedia*. They usually come through winter outdoors in free-draining soil, and grow 30–90 cm tall. The RHS English lavender guide adds that *L. × intermedia* flowers slightly later, and that even though English lavender is generally hardy throughout the UK, you should avoid planting it in cold spots.

French lavender (*L. stoechas*) and other tender types are less hardy and often short-lived. The RHS grows them in containers and keeps them frost-free in winter, for example in a greenhouse.

Buying plants

The RHS says lavender is usually sold in containers of 9 cm or larger, ready for planting. It is also sold as plug plants, which are cheaper but need months of care before they can be planted out.

Be careful with imported plants. The RHS says lavender is one of nine plants considered to be a high-risk host for the bacterium *Xylella fastidiosa*.

Sun and soil

Lavender needs full sun and fast-draining soil, the RHS says. It is happy in poor, dry or moderately fertile soil, including chalky and alkaline soils. It does not do well in heavy clay or ground that gets waterlogged.

The RHS English lavender guide says lavender hates heavy wet soils, particularly in winter, and dislikes shade. It thrives in poor, sandy or chalky soil.

If your soil is heavy, the RHS plants on a 20–30 cm mound or ridge, or in a raised bed.

How far apart to plant lavender

The RHS gives two spacings. In groups, space plants about 90 cm apart. For a hedge, space them 30 cm apart, or 45 cm for larger cultivars.

Lavender in pots

The RHS uses a container 30–40 cm in diameter with large drainage holes. Fill it with peat-free multipurpose or peat-free loam-based compost, such as John Innes No 2, and mix in coarse grit at up to 25% by volume. Plant the lavender so it sits at the same level it was in its previous pot.

In summer, pots may need watering once or twice a week when the compost dries out in hot weather. In winter, keep them fairly dry.

After planting: trimming

The RHS trims lavender every year in late summer, just after flowering. Remove the spent flower stalks and about 2.5 cm of leafy growth. Do not cut into the woody stems, because lavender does not regrow well from them. You can also clip the foliage in spring if it looks untidy or frost-damaged.

Old, straggly plants are best replaced, the RHS says.

Growing lavender from cuttings or seed

The RHS takes softwood or semi-ripe cuttings from young plants in early to midsummer, or hardwood cuttings after flowering in late autumn. Cuttings give plants identical to the parent.

For seed, it collects seed from dry seedheads in late summer, stores it over winter and sows it in spring in peat-free seed compost. Seed from cultivars may not come true to the parent.