the one part you missed out was adding DRE to bench pokes, which count as 2 grass energies, and some scramble that count as 3 when you're prizes behind.
One similar combo is Venusflora, which uses Venusaur CG (to change all energy into grass), and using green blast, but it's even more slower. (Though you can make use of boost energies to get 30 damage quickly.)