This seems a decent wager. It matches the leaves, and is definitely aromatic. However, it smells like anise or licorice rather than what I'd expect from tarragon. Apparently there's plant called Mexican tarragon that smells like anise, but we are in the frozen wastelands of Canada and it shouldn't be able to survive here as a perennial (as this plant does). Weird hybrid maybe...
Hi @troyunrau, @thererdozensofus is most likely right.
Wild tarragon, Artemesia dracunculus (same sp. as culinary tarragon), is variable in smell/taste. In SoCal, some have no taste, I am told other pop's do.
There is a range map here for Canada and U.S., bonap.net