In a large pot of boiling, salted water, cook the corn until the kernels are crisp-tender, about 5 minutes. Remove from the pot using tongs.
Stir 1 tsp. chopped fresh tarragon and 1/8 tsp. salt into 2 tbsp. softened butter. peel back the corn husks but don't remove; discard the silk. Rub the corn with 2 tsp. herb butter and rewrap in the husks. Grill over medium heat, turning often, until the husks have grill marks on all sides and the kernels are tender, 12 to 15 minutes.