Q. Is lavender perennial? When does it come back each year?
Lavandula angustifolia, which is the species commonly grown in gardens, is a perennial species if grown in USDA Zones warmer than 5. Lavender can be grown in Zone 5 but it will not thrive and may be killed in winter. Other species are more tender.
Also, most lavenders are short-lived and need to be replaced periodically (every 5 - 10 years). They require well-drained soil and a sunny location. Grit or sand can be introduced into the soil to aid drainage. Fertilization is not necessary and they should be watered only when newly planted or in severe droughts.
Lavenders should be pruned immediately after flowering and larger species should be cut back to one third in the spring. Lavenders will be largely dormant during the winter but will start new growth as soon as the weather begins to warm up in the spring.