For the amaro:
In a chilled lowball glass filled with ice, combine the amaro, lemon balm and soda and stir well. Add a burdock root swizzle stick and fresh lemon balm leaf for garnish.
For the swizzle sticks:
Scrub the burdock root well, making sure to get rid of any dirt but leaving the peel or outer layer intact. Cut the burdock root in quarters, making long sticks. You can “whittle” the sticks to make them thinner if desired depending on the size of the burdock root you are using. Drizzle a little lemon juice on the swizzle sticks and refrigerate until use.