Oregano is perennial, although not super hardy. In northern regions this herb may need some protections such as heavy compost or mulching in the fall. Some varieties of oregano can grow as tall as 24" inches with a mounding shape to as much as 18" in diameter.
Most varieties of the Oregano herb flower with white or pink-purple spike like flowers in mid to late summer. If you are planning on using this herb for cooking it is best to pick the foliage just as it is starting to flower for the most robust flavor. You may also want to cut the branches back to about for inches from the base of the plant and hang these to dry, this is just another method of drying.
The Oregano plant is easily cultivated from both seed and cuttings. As with most plants it best to take cuttings from new growth well before it starts to flower.