Ningal

Ningal is the goddess of reeds. She is married to Nanna, the moon god. She does not have a prominent role in any Mesopotamian myths that survived the ages of time.

Ningal is the mother of Inanna, Ereshkigal, and Utu. So even if her own stories did not survive time, the stories of her offspring certainly did. How is that for a goddess of water vegetation?