Auguste's sapling

Auguste's sapling is given during the Enlightened Journey quest by Auguste to grow into a Willow tree in order to obtain Willow branches to build the basket of the balloon for the Balloon transport system. The branches can be cut off any Willow tree in a farming patch, or they can be bought on the Grand Exchange. If you somehow lose it or the tree dies, you can buy another from Auguste for 30,000 coins.