I think that Arcane wonders will stick with the druid and vines. However, they will most likely remove the Treebond ability and replace it with something different. Also, a mana saving ability would fit perfect since the druid with 2 trees is extremely powerful and EXTREMELY efficient in mana.
Decomposition: Whenever a corporeal living creature is destroyed, place decomposition tokens in the zone equal to the level of the creature. Whenever you summon a 'plant' creature or conjuration in that zone, you may reduce its mana cost by 1 per decomposition token removed.
That way it is like the phoenix yet it is not related to fire.
Yay!
PS: And idea is to instead of decreasing mana cost, it would require multiple tokens to instead place a growth marker on the