The second floor of Booze's tavern in the Pirate's Den holds a distillery where a man named Alister brews rum for the tavern owner. He is an ornery sort, though, and dislikes having others in the distillery; he will even chase away others, such as the Nameless Hero.
His assistant Elia is a bit more amicable and will talk with others. In the course of conversation, if the Hero continues to mention bloody mary, he will ultimately offer to give a recipe for making the drink, in exchange for 10 bloodroots.
Primary Method Edit
The plant is found in a variety of locations; if you make a habit of picking all the herbs you find during the game, acquiring 10 bloodroots should be very simple.
Alternate Method Edit
Elia mentions that Colby is willing to trade 3 bottles of rum for 9 plants as well. Colby's location is first at a waterfall up a little bit from the main group of buildings in the Pirate's Den. If you have completed the Water Carriers quest and chose Colby to take over for Fence, Colby will move to the camp's Large Gate.
This method is a trade-off. While you save time in not having to search for the plants, you lose 3 healing items as a cost. As mentioned in the Primary Method, if you normally collect and keep all herbs you find throughout the game, no significant time will be spent on the collection of the plants, making the Alternative Method less appealing.