Seeds 100 Seed (Lavandula dentata)

French Lavender (Lavandula dentata) stands apart from common English lavender by its distinctive fringed, toothed leaves and soft, warm-camphor fragrance. The narrow silver-grey foliage forms a tidy, mounded shrub topped by gentle lavender-blue flower spikes, often crowned with small bracts. Its long flowering habit and aromatic, ornamental form make it a favourite for sunny garden borders, low hedges, container displays and fragrant cut bunches.

Planting

Direct seeding is not recommended; instead start the seed indoors in flats or trays and transplant later. Sow roughly 8 to 10 weeks before the last spring frost. Use a soilless seed-starting mix and sow about 3 mm deep. Lavender needs some light to germinate, so cover the seed only very lightly, for example with a little perlite. Keep the medium at around 18 to 21 degrees C; a heating mat providing bottom heat improves results. Germination usually begins in about 14 to 21 days. Transplant seedlings into individual pots once they are large enough to handle, then move them to their final spot in spring after the last frost. Plant shallowly, so the soil line sits just above the top roots. Space plants about 30 to 60 cm apart, choosing wider spacing for better airflow. Lavender demands full sun and will not thrive in shade. Give it light, well-drained, gravelly soil that is poor to moderately fertile and neutral-to-alkaline; avoid heavy clay or waterlogged ground. On heavy soil, plant on a 20 to 30 cm mound or in a raised bed to guarantee sharp drainage. Expect bloom in late spring and summer.

Fertilizing

Lavender needs very little feeding because it actually prefers low-nutrient soil. One option is a single application of slow-release fertilizer for the whole season, roughly one tablespoon per plant. Alternatively, work about 2.5 cm of compost in under the plants. When grown in the ground in suitable soil, no feeding is generally needed at all.

Care

After transplanting, apply about 3.8 L of water per plant each week until the plant is established, watering newly planted lavender regularly through its first summer. Once established it is very drought tolerant and needs water only during prolonged dry spells, so take care never to overwater. Mature plants need only about 1.9 L of water every two weeks until flower buds form, then once or twice a week during flowering. Trim annually in late summer after flowering: remove the spent flower stalks plus about 2.5 cm of leafy growth, but never cut back into old bare woody stems, as lavender does not regenerate well from old wood. The main disease to guard against is Phytophthora root rot, caused by overwatering and wet or heavy soils, so keep drainage sharp and avoid waterlogging. Watch for cosmetic pests such as rosemary beetle, sage leafhopper and cuckoo spit; grasshoppers can reduce yields and deer may browse the plants.