http://www.wowdb.com/spells/56241-gl...erdant-spheres
Bah, this doesn't make sense lore-wise. Embers are more elemental in nature, as they came from fire lord. Verdant spheres are arcane, capable to store arcane magic, as well as parts of souls.
If they implement whole fel fire theme to destro, only then you could justify this. Embers would not be plane elemental fire embers, but fel fire embers, as those came from corrupted arcane magic, and then you could store them in Verdant spheres.