I grow it. French tarragon never survives over winter for me and I am in the south east of England. The Russian tarragon I have comes up every year and is at least 5 years old now.
It’s milder and fresher tasting, but good in salads, coleslaw and for adding at the end of cooked dishes. If you want to preserve it over winter, I would go with freezing it in ice cubes, as drying it seems to rob it of most of its flavour.