Plague of pink

Since we moved out here I've grown familiar with the local flora and fauna, so I was a bit befuddled by the pecular blossoms I saw along the roadside today: kind of pink, kind of fluffy, kind of like what insulation might look like if it grew like a weed. Which is exactly what it was: little wads of pink insulation stuck on roadside weeds like a crop of building supplies. That remote stretch of road tends to sprout strange crops: McDonald's bags, beer bottles, and once a plague of plastic knives. Who throws this stuff there? Why? And what can we do to make them stop?