French tarragon is grown for its narrow leaves (up to 2 inches long) that are beloved for their sweet anise flavor.
 
The flowers are tiny, pale green, and sterile. French tarragon can only be propagated by cuttings. There are many imposters, but it is the tingle on the tongue and the anise flavor that identify the true culinary tarragon.
 
Sold in a 2.5" pot.