How to Prune Egyptian lavender?
Shorten flowered shoots to about 1.5–2.5 cm from the previous year's growth. If flowering is on last year's growth, prune after flowering; if on current-year growth, prune the following early to mid-spring.

Egyptian lavender · Lavandula multifida
Grow in very well-drained, ideally alkaline, soil in full sun. May survive outdoors in mild, dry areas, otherwise grow in a container and overwinter under cover, or treat as an annual. See lavender cultivation for further advice
Shorten flowered shoots to about 1.5–2.5 cm from the previous year's growth. If flowering is on last year's growth, prune after flowering; if on current-year growth, prune the following early to mid-spring.