So Dandelion's beta cost is 109 gems (and will be introduced in the Easter 2015 Pinata Party Event of the next update).
Appears on these pages
Cool! Dandelion, Vasebreakers, and, Costume merging? It sounds like Eggbreaker is a Vasebreaker...
I can confirm that Dandelion will be premium plant in the next update 04:08 Plants vs Zombies 2...