Gilbertson can be located nearby the Seed Shop attached to a tree. He has a decent quest if you want free Mystic Sap for just a single Pixie Watering Can. He's always attached to a tree trying to move it.
About Quest Edit
|???||Retrieve Pixie Watering Can and receive Mystic Sap in return.||1 Mystic Sap|
|"ey ask me to move this tree"
" m givin my best but 'tis not movin!"