Out of curiosity, why didn't you play Rose Gardener, then water Fairy and then evolve Gardener? Won't that allow you a draw or I got that wrong? Also you can activate Spells even if you reached the 5 zone limit?
I'm pretty sure the rule is whenever you have more than 7 cards in hand, you have to discard cards until you have 7 again right after. So silver bolt at max can only deal 7 damage.