Abstract Wild hemp (Cannabis sativa ssp. spontanea) is a rapidly spreading weed in Hungary that forms large and stable patches in most agricultural fields. To evaluate the dominance properties and the nutrient uptake of wild hemp, we carried out experiments in a 36‐ha agricultural field, using 80 evenly distributed sampling areas that were identified by GPS coordinates. Field maps of wild hemp infestations were formulated to determine the density and dominance of this weed, and plants were analyzed for macroelement (nitrogen, phosphorus, potassium, and calcium) contents. Wild hemp showed significant competitiveness against winter wheat, greatly reducing the availability of nutrients to the crop plant. After localizing patches of wild hemp and other weeds in the field by GPS coordinates, a weed contour map was created. These maps were divided into manageable blocks and a site‐specific weed control technology was designed to reduce herbicide use, thereby decreasing the costs and environmental impact of wild...