Feinan, Arbor Tender

{t}, Sacrifice another creature: Exile a Treefolk,
Dryad, or Plant creature card from your hand
and put a growth counter on it.
At the beginning of your upkeep, put a growth
counter onto each creature card exiled with
Feinan, Arbor Tender's ability. Then, if the
number of growth counters on a creature card
in exile equals or exceeds its converted mana
cost, put it onto the battlefield without
paying its mana cost.