Lavender must be cut back every year to encourage a compact growth habit. If this semi-shrub is allowed to grow for several years without this kind of support, its woody branches will collapse and it will grow bald from underneath. The ideal time for cutting back is late summer, when the plant has finished blooming. The lavender should now be trimmed over the old wood by half or a third of its height. This encourages bushy growth guarantees countless fragrant lavender blossoms the next year — sometimes even that very fall.
Before lavender is cut back, its blossoms can naturally be harvested, in order to be dried and turned into sachets, for example. The fragrance lasts longest when the flower spike is cut shortly before full bloom, when a couple blossoms remain closed. Then cut the stem about 4 inches beneath the blossoms.