Once you get onto Route 20, you're going to have to start fighting Trainers, who typically use Pokemon at a higher level than those found in the wild. You get more EXP for beating them, though, making it very rewarding to fight them. You also earn prize money (I just use the $ sign for that).
The first Trainer you have to fight is a Youngster guarding the bridge. He has a Patrat L4 on his team. Further on is a Lass who uses a Purrloin L4. Go ahead and take the two of them out (they shouldn't be too tough) and then you'll be able to access a patch of tall grass. Inside of the tall grass is a Parlyz Heal. There's also another Youngster in there that uses a Patrat L4.
|Route 20 (Spr/Aut/Win)|
|Pidove||Lv. 2, 4||25%|
|Sewaddle||Lv. 2 ~ 4||35%|
|Purrloin||Lv. 3 ~ 4||15%|
|Route 20 (Summer)|
Lv. 2 ~ 4
Lv. 2 ~ 4
|Purrloin||Lv. 3 ~ 4||14%|
The Pokemon you can find in the tall grass in certain areas varies by the season it is in the game. Remember, if your DS's clock's month is set to January, May, or September, it will be Spring; if it's set to February, June, or October, it will be Summer; if it's set to March, July, or November, it will be Autumn; and if it's set to April, August, or December, it will be Winter in your game. Thankfully, the only change here is Sunkern is a lot more common during the summertime, while it is comparatively rare elsewhere in the year. It will also be raining if it is Spring, so keep that in mind and avoid using Tepig's Fire-type attacks in the rain, as their power will be weakened.
= Pokemon Review: Sunkern==
Sunkern is literally the weakest Pokemon in the game — its combined stats are lower than even Magikarp's. It's terrible. It has to deal with Absorb until level 10, which is pretty bad, but thankfully gets Mega Drain at level 10, Leech Seed at 13, and Razor Leaf at 16. On top of that, it gets Giga Drain at level 22, but that's probably the best of its moves for a long while anyway. At least it gets GrassWhistle at level 7, which can put the foe to sleep, although it is very inaccurate (55%).It evolves by using a Sun Stone on it, and you get one of those around the time of the third Gym, which is a Bug-type Gym, so you probably don't care anyway. It gets Petal Dance at level 28 as a Sunflora, though, so make sure you evolve it before then, because that's a good move. Unfortunately Sunflora's stats are really underwhelming. It is slow as molasses and has low Defense. Its Special Attack is impressive, but it's just too risky using a slower Pokemon with Petal Dance like that.I don't recommend using Sunkern or Sunflora. They are easily outclassed as a Grass-type by Sewaddle, who becomes very useful. But at least it does learn Petal Dance and Giga Drain, which are things that Leavanny cannot do.
Sewaddle is a little Bug/Grass-type that has a mix of things going for it. It'll start off rather unimpressive, but picks up Bug Bite at level 8, which hits pretty hard, and then Razor Leaf at level 15. It evolves at level 20, but you're going to want to ride your Bicycle (if you have it) back and forth for about fifteen minutes to raise its happiness high enough to evolve it again (after an additional level up), because Leavanny is an awesome Pokemon.Leavanny has great Attack and Speed, but all of its stats are well within reasonable range. It has a lot of weaknesses, which is one of its major downsides, but its good moves make up for that. As a Leavanny, it gets Slash at level 29, Leaf Blade (hurray!) at level 36, and even X-Scissor at level 39, although you can also teach that via TM around the same point in the game. It even gets Swords Dance at level 46 and Leaf Storm at level 50 to blow away some of its Special Attack it isn't using. Shadow Claw, Aerial Ace, and even Return are good options for it. Surprisingly enough, it can even learn both Light Screen and Reflect from the TMs in Nimbasa City, so it can help support your team as well.All things considered, I really have to recommend using Leavanny, unless you're using Snivy and don't want to get rid of it (you really shouldn't use them both together). It's a very solid Pokemon, a strong attacker, has great moves, and it will get the job done nicely.
Ah, Pidove, the obligatory bird Pokemon to find in the game. It is a lot less impressive than birds in the previous generations, and it is no exception in Black 2 and White 2. Its stats are pretty weak until it evolves for the first time at level 22, into Tranquill, and then it evolves once more, into Unfezant, at level 31. Unfezant's stats are alright, but the main problem is they underutilize all of the interesting Special-based attacks it learns; it has pretty lousy Special Attack. Its Attack is not too shabby and its Speed is certainly fast enough, but it doesn't really learn moves to go with them.Super Luck is definitely the ability you want for your Pidove, because it boosts the chance of getting a critical hit, and that makes a big difference. Combine that with a Scope Lens or Razor Claw and you've got a critical hit machine. It also gets Air Cutter at level 15 to further your chances of getting a critical hit, but, like I said, it's Special-based and the Pidove line's stats are most certainly not. You're really best off just slapping Fly and Return on it, although it can use Roost, Taunt, FeatherDance, Protect (TM), and Toxic (TM) for some very interesting stalling tactics to wear the foes out.I can't say I recommend Pidove. If only it had its Attack stat switched with its Special Attack, it would be really fun to use, but it's just like trying to fit a square cube in a circle hole. It's not the worst Pokemon out there, though, but there are definitely more useful Flying-type Pokemon (although not before the third Gym!).
New Pokemon to catch here are Sunkern, Sewaddle, and Pidove. Sewaddle is definitely the best of the three options, being a useful Bug/Grass-type that is capable of learning useful moves and has good stats when it evolves into Leavanny later on. It also picks up Bug Bite at level 8 and Razor Leaf and level 15, both of which are good options. Sunkern gets GrassWhistle at level 7 to help put the foe to sleep (although it's pretty inaccurate), Mega Drain at level 10, and Giga Drain at level 22. You need to use a Sun Stone to evolve it. Sunkern has very lousy stats, though, so keep that in mind (Sunflora is much better, albeit slow). Lastly Pidove is a rather unimpressive bird Pokemon. It lacks very powerful moves and stats, but it may still be worthwhile adding to your team if you like a bit of strategy.
Just past the patch of grass, there are some rocks scattered around. Press A while facing one of the rocks to pick up a hidden Poke Ball. The Hiker to the east won't let you pass until you've gotten your Gym Badge, so you're going to have to cross the bridge to the west instead.
When you get to the fork in the road, you can head west and then south to hop down some ledges in order to get back to Sangi Town, or you can head north to enter the Sangi Ranch. You may want to take this opportunity to go back and heal, but otherwise, make your way north to the Sangi Ranch.