Yeah, i forgot about the forever sandstorm pokemon (I made the movesets at like 2 am =P). I was looking for Leech Seed in Vileplume's movepool and I didn't see it. I guess its an emerald move tutor thing. Otherwise I would have said that over Synthesis.
Sim's moveset for Vileplume seems rather Taunt weak and it would suck to be setting up a sub when a taunting Gyarados/Crobat/etc comes in. Granted you can switch but it wastes a lot of setup. Thats why I was recommending HP-Rock, it covers several pokemon that will try to wall Vileplume aswell as cover his type disadvantages. Ttar does make HP-rock kind pointless but that is what STAB Energy Ball is for.
Vileplume @ Calm @ Chlorophyll @ Black Sludge
-Stun Spore
-Energy Ball
-HP-Rock/Leech Seed
-Aromatherapy
EVs: HP-134 Def-188 SpD-188
I think this moveset will suprise a lot of people who aren't expecting Vileplume to stay in when it seems walled. HP-Rock allows for better dexterity in combat, leaving it capable in the face of Taunt. Leech Seed has a pretty obvious reason behind it.
You don't play Plume in OU much, huh?
On paper, that *may* make sense.
However, I've tried the two-move thing,it didn't work as well. The Subseed set is a standard for any able to get their mitts on a Leech Seed Oddish. It is meant really for switches. The status set, which I use, really disables teams. Crobat & Gya may have Taunt, but that doesn't save them from switching into the odd Sleep Powder/Leech Seed/Stun Spore. HP Rock may seem great, but in reality, it isn't. In the fast pace realm of OU, it can't afford to be so wishy washy, using HP Rock. Many things switch when they see Plume, promotig status.
And most importantly, even though it covers his weaknesses, don't forget to know the pokes themselves. The only OU fire type is Infernape (Moltres is too rarely seen to count), and he isn't Rock weak -he'll take more from Sludge Bomb. Every poke & their mother has an Ice attack, and hitting a poke wit HP ROCK won't hurt enough to scare them. Crobat can just eliminate before you take it out with HP ROCK, and Ice Fang will put an end to Plume.
If you're scared to use a poke because of Taunt, you're playing it wrong :P
Not that HP Rock doesn'tt have it's merits, but it only its most seen pokes for neutral.