[@BeautyoftheDark] 
She has a few old jars of herbs but she keeps all of the ones she uses in her bungalow; the jars have been left then from when she moved out to the back of the garden .
He can choose to not be seen by Marie (which is a power which all the demons have) and could not mention it too her. There's an odd chance that she might have invited him, but she tends to be wary of the demons on a whole.