It is important to differentiate between the various types of marjoram thyme and oregano as their names tend to get very confusing even to experts sweet marjoram essential oil makes up only a small proportion of the marjoram oils produced most of which tend to be spanish marjoram spanish marjoram oregano is a completely different species thymus masticina and the so called wild marjoram is the common garden herb origanum vulgare cultivated all over the world