I put Marjoram and Oregano together for one good reason, they are very closely related. Like Rosemary, these are also native to the mediterranean.
Marjoram can grow to be a rather large bush (2-3 feet) in southern climates. In the north it won’t stand the winter and must be replanted each spring and then it only has time to grow to a small, 1-2 feet, bush. The tiny flowers are usually white or lavender in color and show up mid-summer. Like we talked about in All Things Lavender, marjoram can be propagated in the same ways; seed, cutting or burying a living stem. Any way you start them, be sure it’s in fertile soil, that is very damp (not root rotting wet though) and in a partially shady spot. Once established it will “self seed” if you let it. Marjoram is a shallow rooted plant making it great for pots too.
To harvest just cut stems or pluck the little leaves. It should be noted that some varieties are ornamental. Sweet Marjoram is the most popular of the “kitchen” varieties. It can be used fresh or dried and is very popular in Italian dishes, sausage and stuffing.
Oregano is usually about half the size of it’s cousin marjoram and can be planted much closer together. It too, comes in a few varieties. Do a little research about the varieties available to you. The wild varieties tend to have much less flavor than a Greek variety for example. I have had oregano make it through a North Dakota winter, we will see about a Minnesota one. Of course it can be propagated in the same manner as above and will “self seed” too. Harvesting is the same as above too. Pretty easy.
Even though both will do well in pots you will notice a difference in the flavor of those grown indoors and those outdoors. Growing them outdoors is ideal.