Noticed that you have received no replies to this. I am the owner of a genuine French Tarragon plant and would be willing to trade for the sage seedlings if you're still interested. You're right to want this plant as it is divine in cooking! You'd have to let me know in advance though as I would have to prepare the cutting for you. If anyone else wants some and has herbs to trade feel free to send me a message and I'll start the cuttings.

do you still need Tarragon?

I do love the anisey zing of French tarragon. I just have it in my perennial garden. Perhaps it likes my zone 4 climate. It dies down to the ground over winter and then springs back stronger than ever when summer comes. I don't fertilize, I don't regularly water - it just grows. Maybe I got lucky and found a sweet spot for it.

i have french tarragon and it starts to go dormant this time of the year, i do prune off the brown stems to about 2 inches , also harvest the fresher looking ones and dry them until the new shoots start up. use it on fish or chop some up when i make chicken salad, ina garten from food network has a good recipe for chicken salad using tarragon,or infuse tarragon in vinegar for salad dressing . when the pot gets crowded i divide them into more pots, while dormant. we don't have snow or hard freeze here in san francisco , so the plant stays out.