French Lavender

French Lavender (Lavandula dentata) is the lavender that keeps flowering when the others have stopped. It forms a rounded bush about 1m tall and 1m wide, clothed in grey green leaves with toothed edges, and in a mild climate it carries soft purple spikes for most of the year rather than in one short burst. The scent is resinous rather than sweet, and it forgives heat, salt wind and poor soil far better than English lavender.

Why you'll love it

• It flowers for months, not weeks. In warm temperate and Mediterranean gardens the purple spikes come and go almost year round, heaviest from late winter into summer.
• The toughest of the common lavenders. Drought tolerant, heat tolerant, salt tolerant and content in poor stony soil.
• A low hedge without constant shearing. One cut a year keeps a 60cm to 80cm informal hedge tight.
• Bees and butterflies work it constantly. The long flowering window makes it one of the most useful plants you can add for pollinators.

Where it works best

Borders and edging. Plant 60cm apart for a low informal hedge along a path or the front of a bed. At that spacing the bushes touch without crowding, and air still moves between them, which matters more for lavender than for most plants.

Mass planting and rockeries. On a dry bank or gravel slope, plant in drifts at 60cm to 80cm centres. Few plants handle a hot unirrigated slope this well.

Pots and containers. A 300mm pot with a gritty free draining mix suits it, and a pot is the only sensible way to grow it in a humid climate.

Growing French Lavender in Australia

Position and climate. Full sun and open air movement. It suits warm temperate, cool temperate, Mediterranean and arid gardens, which covers Perth, Adelaide, Melbourne, Sydney and the inland. It takes light frost only, so hard frosting districts want a sheltered north facing position. In the humid subtropics and tropics it is short lived at best, because summer humidity brings on rot. In Brisbane or Darwin, use a raised pot with sharp drainage and expect two or three years from it.

Soil. Free draining and lean. Do not enrich the bed. Heavy clay is the most common cause of failure, so mound the position 200mm to 300mm and mix in coarse sand.

Water and feed. Water weekly for the first two months, then only in extended dry spells. Overwatering kills far more lavender than drought does. A light dressing of lime every second year in acidic soil does more good than fertiliser.

Pruning. Trim by a third after the main flush, cutting into green growth only. Lavender does not reliably reshoot from bare grey wood, so never cut into the woody base.

What to expect when it arrives

It is grown in two sizes: tube stock and 140mm pots in packs of ten. Both are young plants, which is deliberate, because lavender establishes quickly and small plants settle in better than large ones.

Expect flowers within the first season and full size in about two years. Delivered Australia wide, with delivery from $29.95 and a minimum order of $300 before delivery, and every plant carries our 30 day healthy plant guarantee. One note for pet owners: lavender is listed as toxic to cats and dogs if eaten.

Plant care guides and related reading

• Building a garden around fragrant plants
• Browse drought tolerant plants for dry gardens
• Planning an Australian cottage garden

Common questions

How is it different from English lavender?

French Lavender has toothed grey leaves, flowers over a far longer season and copes much better with heat and humidity. English lavender has a sweeter perfume and better cold tolerance but a short flowering window.

Why did my last lavender die after two years?

Almost always drainage or pruning. Wet feet in winter rot the roots, and an untrimmed plant goes woody and splits open. Mound the soil, water sparingly, and trim a third off each year.

How many plants do I need for a border?

At 60cm spacing, allow about seventeen plants for every 10m of edging. A pack of ten covers roughly 6m.