Boison Vine is much more of a challenge for you than his first form was. For Boison Vine, it spits out various gases at you that can cause a whole bunch of Status Ailments to you, so your best bet is to avoid them. It also throws out Blue Seeds at you and a little vine also whips out to cause pathetic damage to you. To take this thing down, first target its stomach like area that opens up and shows you a yellow part to it.
Hit this and once the inside is hollowed out, head to the top platform by jumping up and switch over to the Knuckles and Salamander or Luna, your call and attack it non stop. Though, if you have not been training the Spirits, they may not be of much help to you, especially if you are not a Class that deals in Magic. If not, then use your Sword to whack the Blue Seeds back at Boison Vine to deal some damage to it. Just avoid its gases and hit the Blue Seeds back at it and eventually it will die.
