If you want to plant “true” oregano, Greek oregano is the one to plant. Oregano is a loose, open plant growing from six inches to two feet tall with gray-green leaves and small purple or white flowers. 
 
Oregano must be planted in a full sun location and good drainage is required for best growth and overwintering.  True oregano is marginally hardy in zone 5.
 
Sold in a 2.5" pot.
 
Image via University of Illinois Extension.