Wither and Bloom

You invoke both death and life in a 10-foot-radius Sphere centered on a point within range. Each creature of your choice in that area makes a Constitution saving throw, taking 3d6 Necrotic damage on a failed save or half as much damage on a successful one. Nonmagical plants in that area that aren't creatures, such as trees and shrubs, wither.

In addition, one creature of your choice in that area can roll one of its unexpended Hit Point Dice and regain a number of Hit Points equal to the roll plus your spellcasting ability modifier. That die is then expended.

Using a Higher-Level Spell Slot

The damage increases by 1d6 for each spell slot level above 2. The number of Hit Point Dice that can be rolled and expended increases by one for each spell slot level above 2. You add your spellcasting modifier to the number of Hit Points regained by this spell only once, regardless of the number of Hit Point Dice rolled and expended.