The nearby gardener will not watch over your growing Goutweed. A Gout tuber can only be obtained while hacking jungles during the Tai Bwo Wannai Cleanup activity, or by trading other players. Sometimes after hacking down jungle during the activity, players will receive a message: "You hack away the remaining bush to reveal an unusual plant." The unusual plant has a 1% chance of appearing when hacking any kind of jungle. Players will need to use a spade on the plant as there is no option to dig it up - doing so gives the player a tuber. Since the chance of a unusual plant appearing is the same for any jungle, the quickest way to obtain a Gout tuber would be to focus on hacking Light Jungle.