I made a grass monotype team and it has been doing very well, but it has some weaknesses I'm not sure how to cover. I'm open to any criticism short of changing my team type.
Serperior (M)@ Life Orb
Ability: Overgrow
EV's: 252 spe, 252 spa, 4 def
Nature: Timid
~Calm Mind
~Giga Drain
~Hidden Power Fire
~Dragon Pulse
Serperior is mainly there because I needed another special attacker and a special wall and he just seemed to fit both roles. He comes in really handy against ice, dragon, and grass monotypes, but sometimes doesn't just have the bulk or power to pull off a complete sweep.
Ferrothorn (M)@ Leftovers
Ability: Iron Barbs
EV's: 252 atk, 168 spd, 48 def, 40 hp
Nature: Brave
~Power Whip
~Gyro Ball
~Leech Seed
~Protect
Ferrothorn is my jack of all trades for the team. He can sponge those pesky outrages and strike back with a powerful gyro ball. He can also abuse leech seed and leftover very well and I have used this tactic with protect many times to save Ferrothorn from what could have been the end.
Torterra (M)@ Leftovers
Ability: Overgrow
EV's: 252 hp, 200 def, 56 atk
Nature: Adamant
~Body Slam
~Wood Hammer
~Earthquake
~Rock Slide
Torterra is my false lead. Most opponents will think I will throw him out as a stealth rocks setter, but this isn't the case and I can normally paralyze the opponent with a body slam and then proceed with however I deem fit.
Breloom (M)@ Focus Sash
Ability: Technician
EV's: 252 atk, 252 spe, 4 hp
Nature: Timid
~Spore
~Swords Dance
~Mach Punch
~Bullet Seed
I don't think Breloom needs much explanation on why it's on my team. It has won countless battles for me when all hope seems lost and finds its place on just about any grass or fighting monotype team.
Cradily (M)@ Lum Berry
Ability: Suction Cups
EV's 252 hp, 252 spd, 4 atk
Nature: Careful
~Curse
~Recover
~Seed Bomb
~Rock Slide
Cradily is probably one of the most overlooked pokemon in existence. With this kind of special bulk and option of physical bulk Cradily has made many people rage quit against my team because they find it near impossible to KO when he gets up and running (or maybe walking would fit better with THAT speed). Cradily has swept many teams and people have changed their team specifically for Cradily when rematches take place.
Tangrowth (F)@ Leftovers
Ability: Regenerator
EV's: 252 hp, 252 def, 4 spa
Nature: Modest
~Giga Drain
~Hidden Power Rock
~Leech Seed
~Synthesis
Tangrowth is my physical wall capable of taking any brave bird flying pokemon can dish out and deal super effective damage back with HP rock. That's pretty much all it's there for as she has trouble dealing tons of damage, but has saved my team multiple times from the likes of flying teams.
That's my grass team and as far as weaknesses go I have ice and flying pretty much covered, but I always seem to struggle against fire, psychic, dragon, and ground teams. I don't understand why I struggle against ground, I just do. This team has come in second in 8 tournaments, but has yet to bring home the first place trophy. Once again I am open to just about any advice.

Serperior (M)@ Life Orb
Ability: Overgrow
EV's: 252 spe, 252 spa, 4 def
Nature: Timid
~Calm Mind
~Giga Drain
~Hidden Power Fire
~Dragon Pulse
Serperior is mainly there because I needed another special attacker and a special wall and he just seemed to fit both roles. He comes in really handy against ice, dragon, and grass monotypes, but sometimes doesn't just have the bulk or power to pull off a complete sweep.

Ferrothorn (M)@ Leftovers
Ability: Iron Barbs
EV's: 252 atk, 168 spd, 48 def, 40 hp
Nature: Brave
~Power Whip
~Gyro Ball
~Leech Seed
~Protect
Ferrothorn is my jack of all trades for the team. He can sponge those pesky outrages and strike back with a powerful gyro ball. He can also abuse leech seed and leftover very well and I have used this tactic with protect many times to save Ferrothorn from what could have been the end.

Torterra (M)@ Leftovers
Ability: Overgrow
EV's: 252 hp, 200 def, 56 atk
Nature: Adamant
~Body Slam
~Wood Hammer
~Earthquake
~Rock Slide
Torterra is my false lead. Most opponents will think I will throw him out as a stealth rocks setter, but this isn't the case and I can normally paralyze the opponent with a body slam and then proceed with however I deem fit.

Breloom (M)@ Focus Sash
Ability: Technician
EV's: 252 atk, 252 spe, 4 hp
Nature: Timid
~Spore
~Swords Dance
~Mach Punch
~Bullet Seed
I don't think Breloom needs much explanation on why it's on my team. It has won countless battles for me when all hope seems lost and finds its place on just about any grass or fighting monotype team.

Cradily (M)@ Lum Berry
Ability: Suction Cups
EV's 252 hp, 252 spd, 4 atk
Nature: Careful
~Curse
~Recover
~Seed Bomb
~Rock Slide
Cradily is probably one of the most overlooked pokemon in existence. With this kind of special bulk and option of physical bulk Cradily has made many people rage quit against my team because they find it near impossible to KO when he gets up and running (or maybe walking would fit better with THAT speed). Cradily has swept many teams and people have changed their team specifically for Cradily when rematches take place.

Tangrowth (F)@ Leftovers
Ability: Regenerator
EV's: 252 hp, 252 def, 4 spa
Nature: Modest
~Giga Drain
~Hidden Power Rock
~Leech Seed
~Synthesis
Tangrowth is my physical wall capable of taking any brave bird flying pokemon can dish out and deal super effective damage back with HP rock. That's pretty much all it's there for as she has trouble dealing tons of damage, but has saved my team multiple times from the likes of flying teams.
That's my grass team and as far as weaknesses go I have ice and flying pretty much covered, but I always seem to struggle against fire, psychic, dragon, and ground teams. I don't understand why I struggle against ground, I just do. This team has come in second in 8 tournaments, but has yet to bring home the first place trophy. Once again I am open to just about any advice.