Green leafy angel

Dominic and Pia pray each night.  Sometimes we pray the Our Father and other prayers. They know the words, but are too young to understand many of the bigger ones, but we slowly explain to them what the phrases mean:

Daddy, Dominic, Pia: "Angel of God, my guardian dear..."

Daddy: <pausing> What does 'guardian' mean?

Pia: Where we plant flowers and vegetables?

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