Also, it's not cumulative, i.e. if you have 1 Venusaur in play you can attach 2 to the active, but if you put more Venusaur out, you still can only attach 2. Also, it replaces your once-per-turn energy placement.
a great place for info is THE COMPENDIUM... http://pkcompendium.hypermart.net/compendium/rulings_compendium.shtml#ppowers and scroll down till you get to HARVEST BOUNTY...