16 feet or longer.

If your flower bed is 4' square, it will have a perimeter of 16'.

If your flower bed is 48' long and 4" wide, it will have a perimeter of 96' 8".

If your flower bed is 4' square, it will have a perimeter of 16'.

If your flower bed is 48' long and 4" wide, it will have a perimeter of 96' 8".