Origanum vulgare youll know as the culinary herb oregano, a common ingredient, especially in Italian cuisine. Order a takeaway pizza and theres probably oregano on it. It grows up to 80cm tall and has purple flowers. Technically it is a perennial, but it wont last over winter in colder climates, so you should treat it as an annual in such conditions. Plant oregano in early spring, in dry soil in a sunny position. It became popular in America after soldiers brought the pizza herb back from Italy with them during World War II.