There is even confusion outside the genus itself. Whether oregano or marjoram, they all are members of the Lamiaceae family, the mint family. Plants belonging to this family are easily recognized by their square stems and opposing pairs of leaves. They also have whorled flower spikes. Marjoram and oregano are similar in appearance.
Oregano tends to get leggier and more sprawling if left unclipped.
Because of its more compact habit marjoram was and is often used in English knot gardens. The flower buds at the end of the stems are covered with modified leaves called bracts which gives them the appearance, until they blossom, of tiny green pine cones. Flowers appear in summer and will last well into the fall. Oregano usually has pinkish purple flowers, marjoram usually has white blossoms. The shape and color of the leaves differ between oregano and marjoram, as well as among the different varieties.