It will take time to load. When a vehicle is driven through a weed infested area, weed seeds may become lodged between the tire treads, in the coils of a winch, behind the license plate, or in cracks and crevices on the underside of the vehicle. The source of many infestations has been traced to roads, trails, railroads and other travel ways. Seeds may travel hundreds of miles before dropping off into areas that had no weed infestation.
Weeds can also pass through the digestive tracks of animals and still grow.
Pack animals can spread a weed infestation new locations days later. Animals that will be moved from one area to another should be fed certified weed free hay at least 96 hours before entering new areas. Their coats should be brushed and hooves cleaned as well, to remove any weed seeds. Because many noxious weeds have pretty flowers, they are often picked and used in floral arrangements. Some weeds can actually develop roots and produce new plants directly from parts, even after weeks of use as decorations.