Per LB CAD
This variety has created so much industry confusion. In fact, you can still find sites online that describe American Tettnanger as a true Tettnanger. In reality, it is a clone of rhizomes imported as Swiss Tettnanger.
Recent tests have shown it to be genetically distinct from the original land race, Tettnang Tettnanger. Instead, the US varietal is more likely a Fuggle open pollinated with Tettnang Tettnanger. The original import was from a region in Switzerland directly across Lake Constance from Tettnang, Germany.
American Tettnanger enjoyed some great popularity early on, being grown in Idaho, Washington and Oregon. It has noble hops aroma qualities with a bouquet of floral spice. However, in recent years, Anheuser Busch abandoned the variety.
It is said that US Tettnanger is a good hop for the boil as well as dry hopping whereas the original German variety is better used as a late addition.
Descriptions by the awesome Hopslist.com