You may do so any time you have priority
Its also solid against one-shot graveyard hate like Endurance or Tormods Crypt if your one mana spell can force its activation, that usually means that you havent used many resources and theres a good chance to rebuild later on with a timely Reunion
Each of these spells has a potential advantage over Explosive Vegetation
Lorcana puts out four sets each year of the game, using the anniversary of the game as the year marker
'That's No Blizzard' is an ability that requires you to play cards featuring Elsa's sister Anna - and there aren't many strong options for doing so
So, Nomads-en-Kor for the ability activation, and a combination of Pearl Medalion, Cloud Key, or Urzas Incubator for cost reduction, and you have a creature able to keep flickering in and out ad nauseum