Roserade won't learn Petal Blizzard!!

Question

I'm playing Pokemon x and I evolved my Roselia into Roserade around level 35( ish) and it is now a level 54 and it hasn't learnt Petal blizzard yet, (serebii says it should learn it at level 50), and it's annoying me because I want it to learn another good grass type move, so does anyone know how I can teach it Petal blizzard, or another good grass type move to teach it.
Current move set is;

Petal dance
Dazzling gleam ( the move I want to replace)
Venoshock
Toxic

Thanks in advance!! ( btw toxic and then venoshock is great move combo!!)

Answer 1

Roserade doesn't learn Petal Blizzard at 50 in XY; Roselia learns Petal Blizzard at L50 in XY. Once Pokemon that evolve by stones evolve, they most usually do not learn moves their pre-evolutions would have learned.

Roselia - DB learnset