From Tolkien Gateway

Agatha was Farmer Giles' wife. When Garm woke up the two of them with the news of the Giant's arrival, she first recommended drowning the dog, but when Giles indicated that he believed the dog she told him to be bold and quick.

When Giles became king of the Little Kingdom, Agatha became a queen of great size and majesty. She was known to keep a tight account upon the household.[1]