Autumnal Days - Aurora Florealis

Hermione knows Snape is not inclined to honor favours, but Snape hates feeling like he owes the trio for saving him. They will be forced to spend time with each other, whether they like it or not. But the Hogwarts grounds seem upset, and the cold spells dangerous. Rare potions ingredients. An undiscovered garden within the Hogwarts grounds. What will bloom? ss/hg. Slow burn.