Yes, looks like a good cover to do. You will be better putting the castle on the ribs above the heart and using the natural curves of the garden to run the fairy tale garden path of happiness down the hip. Hence the wavered path down the centre and only realy covering the outer heart with mash (detail). Other than that yes you could cover it up on the area only in question but you will have to have very dark tones in the castle brickwork.
Obviously online advice is only that.