The garden is small, but every extra bit of plant life is an extra bit of water retaining capacity for the city, and an extra bit of moisture to evaporate into the hydrologic cycle.
In fact, the only way he would be spotted was if his Uncle Vernon or Aunt Petunia stuck their heads out of the living-room window and looked straight down into the flowerbed below.
I often land in the high depression uneven wall, overgrown flower bed next to squat their own body, so that as high as the body and the flower bed, look intently.