Nice way of giving Life some much-needed control. It's patient like mother nature and can speed up the job of Thorn Carapace. It's also not as vulnerable as that shield.
My instinctive reaction is that it could use a cost reduction of 1, especially on the unupped ability cost, but I might be jaded by blindingly fast rush decks and what it takes to stop them. Nonetheless, since it doesn't stop a creature from attacking, I think it'd be fair.