Helping Irenicus' Captive Dryads - Baldur's Gate 2 Side Quest
Helping Irenicus' Captive Dryads is a Side Quest that begins inside of Irenicus' Dungeon during Chapter 1 of the game. To begin this side quest you'll need to speak with the Dryads inside Irenicus' Dungeon and retrieve the Acorns from Ilyich that they ask you for. If you did not pick up this quest at the start of the game then it's permanently missed since you can not return to this dungeon once you leave.
Once you leave Irenicus' Dungeon with the Acorns all that is left is for you to fast travel to Windspear Hills and give the Acorns to Vaelasa who is in the bottom right hand corner of the map. For an exact location of Vaelasa I recommend you check out my Windspear Hills Overview page.
Prior to traveling out to Windspear Hills I strongly recommend you visit Lord Jierdan Firkraag at the Copper Coronet first. He'll give you another quest called Journey to Windspear Hills which you'll want to do at the same time when coming out here.
Turning in the Acorns to the Dryads will net you 32,500 EXP at first then another 9,750 EXP after some more dialogue. This EXP is split amongst your group and not per character.