yes
Roserade can only learn extrasensory through breeding. If you have a Pokemon that already knows that move, try to breed it with Roserade.
You better keep Abomasnow, because he has more strength and can learn more attacks from different types.
a Roselia
use a grass type like roserade because it is super effective against ground types and can help you beat lucian's psychic types as roserade can learn shadow ball too :)
A TM for Cross Poison doesn't exist. Look here to learn which pokémon can learn it by level up: http://bulbapedia.bulbagarden.net/wiki/Cross_Poison
Leaf Storm is not a move that Roserade can really learn. You would have to leave a Roserade and a Pokemon that does know leaf storm in the daycare. Cross your fingers and hope the egg is a budew with leaf storm.
In Pokémon Diamond, Roserade is no capable of learning additional moves or attacks however you can go to the Move Relearner in order to reteach it moves such as Weather Ball, Poison Sting, Mega Drain, Magical Leaf and Sweet Scent.
all the Pokemon on dimmond that can learn flash can still learn flash in the platinum game too
No. In fact, Roserade doesn't learn any moves by level-up. roserade can learn it though from the move tutor
No. Roserade cannot learn Dark Pulse. Sorry.
at level 1 but u need to go to the fat move tutor with heart scale. it wont work for me :(
poliwrath