Level 100 Statistics (see level 5, 50, 100)
Victreebel rarely had a chance to shine in previous generations, having few options to give it any niche. That changes in BW RU, where Victreebel becomes one of the most threatening Pokemon in the game with the proper support. Its great 105 / 100 mixed attacking stats, along with its very powerful offensive moves, make Victreebel a solid Pokemon. But that's not all—under Sunny Day, Victreebel becomes a monster; Chlorophyll doubles its Speed, while Growth does the same to its offenses. Sun makes or breaks Victreebel; under sun it is ridiculously powerful, 2HKOing the entire tier, but outside of it, Victreebel is all but dead weight.
All this power comes at a price, however. Its poor defensive stats mean that even though it can decimate most of the tier in one or two hits, it will only be able to take one attack at best; priority also causes it huge problems defensively. Victreebel also has very limited offensive options, the lack of physical coverage practically requires it to go mixed. Although Victreebel has received very few changes since DPP, it is still capable of obliterating teams with some support.
This is the ultimate sun attacker; after a Growth boost, Victreebel is capable of OHKOing or 2HKOing everything in RU. As the intent of the set is to cover the entirety of the tier, Victreebel's two STAB options, Leaf Blade and Sludge Bomb, attack off both the physical and special side, leaving nothing safe from its deadly assaults. Weather Ball is the key to this set, giving Victreebel perfect coverage, as well as a 100 Base Power Fire-type move under the sun, allowing it to gain a pseudo-STAB from the weather. The power this set provides is ridiculous, with only maximum Defense Munchlax, a niche option at best, able to withstand Victreebel's onslaught.
Team Options & Additional Comments >>>
Outside of the moves already mentioned, Victreebel has very few alternative choices. Sucker Punch is Victreebel's only form of priority, and can be used to pick off weakened Pokemon or Pokemon who could outspeed and threaten Victreebel. However, it generally lacks power without any boosts to back it up. Encore is an option that can grant Victreebel turns to set up; for example, Victreebel can Encore a wall using Toxic, and use this time to set up Growth. Unfortunately, this greatly reduces Victreebel's coverage and leaves it more vulnerable than it should be. A Swords Dance set is an alternative option to the mixed set; with a set of Leaf Blade, Sucker Punch, Swords Dance, and Return, Victreebel can hit most of the tier hard. However, this set struggles greatly with Steel-types and physical walls in general, only managing to 3HKO Steelix with a +2 Leaf Blade.
Checks and Counters
With the immense power Victreebel wields, it is very difficult to find a Pokemon to take it on. If Victreebel is given the chance to set up, nothing in the tier is capable of avoiding a 2HKO. That said, Victreebel suffers from frailty, so attacking it immediately can weaken it to the point where a clean sweep is not an option. After it sets up, the best way to stop it is with smart switches that can outstall the sun turns and increase Life Orb recoil damage. Choice Scarf variants of base 100 Speed Pokemon, such as Typhlosion, are able to outspeed Victreebel in the sun, thereby revenge killing it before it wreaks too much havoc. The bulkier Pokemon in the tier can take one attack and fire back in return; Throh is the best option for this, but Gallade is also a good choice. Strong priority such as Entei's ExtremeSpeed or Absol's Sucker Punch will put Victreebel in a position where it cannot use more than a couple of attacks before fainting to Life Orb recoil, possibly even KOing it if Victreebel has switched into entry hazards.