celebei
In Pokemon Diamond i say Torrterra is the strongest grass and ground Pokemon because i have a level 100 one and it's great.
Grass-type Pokemon are weak against Bug, Fire, Flying, and Ice-type attacks, but any type can damage a Grass-type Pokemon, either great or small.
Shaymin and every starters from each region
search in the great marsh in the grass or trade with your friend
There are no grass type Pokemon underground!
use the Pokemon radar in the great marsh until you see the grass tiwinkle
Torterra is a Grass and Ground type pokemon.
Well, i would go with the grass type. It will at least get you started, and later on you can get some really great fire and water types. There aren't very many strong grass Pokemon in these games. If your looking for a good way to start, go with the grass!
That's a matter of opinion, but I think the worst Grass Pokemon is Paras, compared to all the other grass Pokemon I know of it is the worst.
Water Pokemon with water attacks or Grass Pokemon with Grass attacks
Roselia is a Grass and Poison type pokemon.
By moving clumps of grass in pokemon emerald.