Lavender is a Mediterranean shrub that needs full sun and very free-draining, low-fertility soil. Wet winters kill it more often than cold.
See this plant in the collectionSun
Full sun
Soil
Poor, free-draining
Soil pH
6.5 – 7.5
Water
Drought tolerant once established
Plant in gritty, free-draining soil.
Avoid rich compost and heavy feeding.
Trim after flowering, not into old wood.
Water only during establishment.
Every figure above comes from these pages.