Assuming you're using Roserade in UU, I really think Spikes is the best option. While poisoning the opponent upon it switching-in sounds sweet, Spikes damages the foe, and has the right stats to lay several layers. She gets Giga Drain to heal herself, Sludge Bomb to hit hard from that great 125 base SAtk, and Rest to fully heal herself and switch out with Natural Cure. Toxic Spikes should only be used in Stall teams, or even better, in Hail Stall teams. Stun Spore can even be put somewhere in there, but it's really hard to find a place for it.
Also, you can't have two Pokemon of the same species on the same team in competitive battling.