UU IMO. It's just not up for OU, really. Grass is usually a poor attacking type (only really useful for Swampert and a few bulky Water-types who usually carry Ice attacks, anyway), and is walled by Skarm, Blissey, Tentacruel (ruins its Toxic Spikes, BTW), Aero as a Taunter, Ninjask, who can 2HKO with X-Scissor, Empoleon, who can Avalanche it while not being OHKO'ed by anything it has, Gengar, who outspeeds and deals heavy damage with Shadow Ball, Dusknoir, who can Ice Punch it while taking little damage from even Leaf Storm, and other Taunters such as Azelf, and is also pwned by LeadApe. The list goes on and on. Poor Roserade IMO. Just because it learns Toxic Spikes and Spikes, and has passable Speed, now it's OU. I hardly see it in OU anyway, and when I do, it's easily dealt with by Ice and Fire attacks, which are both extremely common on teams because of Salamence and a certain red bug.